been reading slowly and I try to understand from where the op is coming from, that said never in my life have I used the term "boys/BOI".
one thing that the OP has to take in consideration is that this forum is international and English is not every posters first language, there are people here from many countries, languages, ethnicities, cultures, etc.
in many languages the male pronoun takes precedence, always. in very little occasions the female counterpart is used, in Spanish, Italian, Greek even in Japanese I have seen that the male pronoun takes precedence even to connote neutrality.
an example;
in Spanish if there is a group of people lets say 3 males and 3 females, and you use the term in question, " lets go everyone", you will use the term " vamos or vamos todos", "todos" is a male pronoun even if you are referring to the entirety of the group, it becomes neutral but is still male predominant.
now lets say you have another group of persons but this time the majority are female but there are two males, you will still use " vamos or vamos todos", even if in the group the majority is composed of the female counterpart. the same happens in Italian.
I understand your point op and the message that you are trying to carry, but language has not evolved yet to a definitive word that is totally neutral. and is like you said communication is more than a two way street , but don't be so hung up because "boys" is derogatory to you it does not mean that a lot of folk are using it maliciously. hopefully language soon will be even more varied and come in many flavors.