This one is not straightforward to judge.
Before I express my opinion on the thread - I want to be clear on my own position on what it raises first.
Firstly - I love women round the table. I actively encourage it. I normally GM and find as a man in this position that I enjoy the different dynamic of the female mind and the (for me as a male) less predictable ways a female player will have their character approach resolving problems or encounter. I also try make sure that players wanting to play people of the opposite sex are those capable of doing so without slipping into sexist cliché. I've seen that passively offend, and frankly it makes my left eye twitch to see it. I also recently withdrew as GM from a game at an RPG club due to sexual-stereotyping proxied through a female player's character which she was uncomfortable with. I told the organisers, and I apologised to the woman that it had happened 'on my watch' even though I couldn't really do anything about it when it happened.
Second - I have roleplayed since it was invented, and LARPed pretty much the same. I have encountered increasing numbers of women in both as the years have gone on, and this has generally made the hobby richer and more enjoyable.
I have witnessed only four other instances of sexism or sexually inappropriate behaviour in all that time, and two of the instances were dealt with appropriately. One was ignored in very much the same way as described the blogger, and in one the culprit was a woman. Twice these events involved police, who on both occasions acted quickly and appropriately.
I have been gaming for 37 years, I regularly do conventions and have LARPed for 20 years.
So I have to ask myself why I haven't seen much of this? I think the problem is 'selection bias' - and it is something everyone should try to take into account as they consider their own experiences. After all - the common thread of any experience you have is that YOU are the one there - and in 'RPG-land', you are commonly around your friends, and one doesn't make friends with people one doesn't like...
... so.
Let us assume for one moment that the blogger at the other end of the OPs link is a young, attractive woman - and thus will attract more unexpressed sexual attention than the average.
Let us also assume (as seems to be the case from the examples) that this most often occurs at open gaming days in shops and at conventions - and thus there is a larger gaming population to be found in immediate proximity.
Let us of course assume (because it is true) that the majority of gamers are male.
This makes it more likely that (a) there will be at least one maladjusted male in the vicinity, and (b) that the woman will attract their attention and perhaps a follow-up action like those described.
On a probability basis this all seems sound.
There is some 'sample bias' evident in the blog however. I would expect a mixture of 'don't know how to react' responses, 'he's my mate and I need to cover for him', and even reputational defence reactions from organisers now and again... but the complaints to police going undealt with, seemingly without exception?
That doesn't match my experiences - and my own 'sample bias' did not affect that one iota. I have to say that I also do not appreciate the male stereotyping the angry voice of the blogger descends into by implication - but I can understand it. We all go overboard to some degree when angry, so I'll leave that there.
But I do have to consider that as a white male, ex-military, confidently outspoken and the kind of person who will unhesitatingly speak out and act the MOMENT I see a hint of this sort of nauseating behaviour (my friends are similar, and the people around me generally know my opinions on this...) that I roleplay with people who agree with me on this, and elsewhere walk around in a bubble of 'don't try that near this guy'.
So applying logic to this analysis, the only reasonable course is to assume that I suffer from my own 'sample bias'.
I haven't really thought about this sort of thing from such a point of view before, and I suspect the vast majority of us haven't.
I think we should, and apart from making a firm commitment to stamp on this when we witness it, and to go out of our way to ensure it is dealt appropriately, we also need to go a step further.
At conventions, big meets, game shops and of course in our own games - include a reference or two (in anecdotal style at the very least) to what we think of such behaviour, how offensive it is and how utterly unacceptable we find it.
On the one hand this will send a clear message to those hearing it, that they have 'permission' to express the same if they witness something (putting this into the mix early means 'shock' inaction or excuse-making is far less likely). On the other hand, the gutter-minded types will know that they need to keep their pathetic urges or bigoted opinions firmly to themselves if they don't want to suffer the consequences...
We shouldn't give a rat's ass whether our fellow rpg'ers are male, female, black, white, liberal, conservative, atheist, agnostic, religious, straight, gay, undecided, trans-sexual or whatever, and you know why...?
... because we are about to step into a world where different races, religions, cultures, monsters, magic and other damn strange stuff interacts on a daily basis, usually staring in a pub, and ending in the kind of place you would never consider retiring to because of the violent crime rate being above the national average...
'Preventative maintenance' of a universally open and accepting environment in which we can all go to that world without dragging in real-world prejudice into it requires our active involvement even if we are passively paragons of virtue ourselves.