I am really sorry to hear you had such a negative experience at your recent conference. Small children can definitely be a disruption under any circumstances and I cannot imagine how difficult it would be to adequately hear a presenter with boisterous children nearby.
As to your first comment, I would urge you to extend some compassion to individuals who do not or cannot stand up for themselves. An individual who has been the victim of trauma or abuse is not inherently 'mentally weak' and did not necessarily 'skip a part of growing up'.
Consider for example:
In the late 90s and early 2000s it was a common part of the gamer vernacular to use the term 'rape' in a way that was synonymous with 'pwning', '0wning', or otherwise overwhelmingly beating someone in a game. This terminology was incredibly insensitive (and psychologically damaging) to gamers who were victims of sexual assault, and many venues and gaming communities had to introduce rules to forbid its usage (alongside other epithets and hurtful language).
These rules were not intended to give victims of abuse a 'false sense of security' they were intended to raise awareness within these communities for what was considered acceptable behavior, and to educate individuals who (despite acting without malice) did not consider the potential harm they might be causing others.
Likewise, someone who is part of a marginalized group, or someone who a Code of Conduct is intending to protect, should not need to independently apply social pressure to every individual who cannot conduct themselves with civility. That is an unfair burden of expectation to place on the shoulders of few, when the responsibility belongs to us all.
While I would love to live in a world where people can behave with empathy and compassion for others, the undeniable reality is that bad faith actors will always need some explicit rules. Otherwise, they will merely hide behind the façade of "No one said I couldn't do x, it's not against the rules!'.
And yes, I believe it is 'ok if the mentally weak feel welcome', I do not believe you should need to be an emotionally impervious hero to wish to attend a social or professional gathering.