Snarf, just stop.
You're convinced there's something wrong with the system. No matter what I tell you, you come across as completely convinced it can't be for completely legitimate reasons. The more we talk, the more I see you trying to paint me as some protector of a shady implementation, when I only engaged to give you my version of a technical explanation.
I did not use the phrase "you can't accept" to refer to anything more than my message. You're setting up a straw man here, by "respectfully" saying you don't agree with a position I don't have and haven't stated. The only approach leading to toxicity here is yours. Stop alluding that I might confuse rules that work well in real life interactions with those that work on-line. It's a cheap argumentative trick, and it derails from the topic.
The topic is: what you see isn't there. It's just you. There's nothing suspect with the way XenForo works.
But if you refuse to listen to me, perhaps you'll listen to Morrus instead. Here's his post introducing the functionality:
Now please drop your suspicion that there's somehow something questionable with the way you can't keep people you've ignored out of threads you start. The function has been deliberately set up this way by people that do care. Not "programmers". It is set up this way to protect you - not "those who wish to wade in". Other platforms might do things differently, but EN World isn't different for the suss reasons you try to allude to.
?What?
I honestly don't know how to respond to this. Try looking back at the conversation. I was (gently) pointing out that different defaults end up with different ... results. Right? Pretty basic stuff. If you have an opt-in as opposed to an opt-out, changing that default has a meaningful difference.
That was it. You keep going back to the same idea that you do here ..... about keeping people out of threads. Which is really a weird way to look at things. That's .... that's a you thing. If you are looking at this in terms of power dynamics and pulling one over on you* as opposed to ... I don't know ... people that just don't want to engage with certain types... I can't change how you view things.
But I think there might be a correlation you're missing.
*In most contexts ... trying to frame the idea that you have the right to intrude when someone doesn't want you around ... is not looked on favorably.