Hiya.
As you later note, the treaty was not made to address ship to ship combat, or protect bases in space. It was designed to keep space from being militarized against the Earth.
Insofar as the treaty also states that no country can claim territory on any celestial body, that is the case. We plant flags, but those do not indicate ownership.
Nations do retain sovereignty over things they put in space. That's a reason why weapons are allowed - to allow self-defense. Plus, in space what qualifies as a "weapon" in general is a bit difficult to classify. Anything that might puncture a space suit may be considered a weapon, after all.
There is no such penalty. Even wars do not provide such a penalty.
Your personal guarantee? I guess that serves to spell out your emotional stance, but even then, it isn't like anyone can or will hold you to that. But I don't think that's convincing.
"Neutral ground" is a concept of tense nations in conflict. Space won't be "safe" to develop in meaningful senses unless we are past that, into a state of cooperation, rather than conflict.
Given that any permanent base on the surface is apt to be using frozen water and other resources on the Moon (or Mars), you are now allowing for free competition for resources - resources that are life and death to the occupants of those stations. Water and range wars ensue. Blood flows.
So, sorry, but "everybody do what you want" will tend to lead to violence.
They (treaties) may have been designed for 'orbit-to-planet' initially, but these are what will lead to precedence. This will lead to court cases, and those court cases will lead to using those treaties as a base. All it takes is for a Judge to think "Naaa...that's silly" and then make a judgement. Now that becomes precedence. Rinse and repeat and...well, we have the completely messed up, bias and virtually useless Court System we have now. Of course, all IMHO.
It would be nice to start a NEW baseline precedence that focuses on "we all have to survive in space together...or we all die together in space"...and where countries "ambitions" take a back seat.
As for the whole "self defense in space"...that's the problem. It goes back to the initial paragraph here; we are trying to use "earth based, country/culture/law" as a baseline for how things should work in space. I think that's bad. Look at the earth. Someone would be hard pressed to say it's all going along swimmingly, no?
We, as a species, have the opportunity RIGHT NOW to do something
different than what we did before. We have the opportunity to say "Ok, countries are fine and all, but in space, there are no countries. Culture is fine and all, but in space, there is no culture. Religion is fine and all, but in space, there is no religion, etc, etc, etc". There is, literally, NOBODY in our solar system right now that we are aware of. Maybe even the entire spiral arm of our little galaxy here. Maybe even in the ENTIRE galaxy. We, as a species, need to look past all those mostly pointless "human hang-ups" we have regarding our personal identities and start thinking of ourselves as "just humans". My thoughts are obvious; the 'laws' we create for space right now should reflect what we WANT to be...not what we THINK we will be.
I am emotional about this, true. But I think a lot of people are...and more people should be. Getting out into space now, with serious "this is happening!" vibes going on for getting a Lunar Base, a "half-way-to-Mars" supply outpost, and a Mars base, needs to be done with a planetary mindset...not one as small and petty as "well, MY country is cooler!".
The whole Moon thing? Yeah...just replace "competition" with "cooperation" and you have it.

Competition means "I want to keep you from getting what I want"...this is the typical American mindset (and many other western-style countries). It's also human nature to want to test oneself against others. I have no problem with that. But the prize should be for prestige, fame and bragging rights...not any sort of monetary gain. So three different Lunar bases 'competing' to see who can extract the most water is a good thing; but once extracted, it ALL goes into the same tank where everyone can draw from it as equal partners (for example). As I said...we have the opportunity to try and get away from how things work here on Earth, and try and form something of how we wished it worked on Earth.
"Everybody do what you want" will lead to violence. Yup. I can't disagree with that. However, as I said, if everyone NOT involved in that violence holds those involved in the violence accountable for their own actions...and it HURTS for them to be held accountable...well, "mutually assured destruction" has worked wonders for all the countries with nukes!
If we can get a spirit and functional system where cooperation and sharing FAR outweighs the "me first" attitude of so many on this planet right now...I think it's a good thing. Right now, space is mostly a blank slate. Might as well shoot for something better than what we have now, right? If we fail at that, I'm sure there will be no shortage of military, pharmaceutical, and technological sociopaths in positions of power to make space just as peaceful and accepting as we have right now.
^_^
Paul L. Ming