I've thought about this subject a bit, so I'll give my very personal take on this matter. No need to respond unless you happen to feel like it, as there are many here eagerly asking for your time.
Why do you think she did not behave as an adult? The two men were already in violation of the code of conduct for the location, which is why the organization took action against them.
Objecting to some off colour jokes because they were sexual in nature seems to me a bit small-minded. Not adult behaviour. I know a few strict religious people who might do that, but really nobody else.
I agree they were literally in violation of the code of conduct. I do think that it's a silly code of conduct, that's far too broad. No dirty jokes allowed? I don't see any reasonable basis for making that a violation of the rules. It's not as if there were a lot of 12 year-olds running around. Mind you, while I've attended a lot of IT-related conferences, none of them had any code of conduct and - to my knowledge - no problems ensued. I did on a few occasions witness some innuendo, from both (apparent) genders (I did not ask about their sexuality).
Coming back to the violation issue, it seems to me the the least part of the issue. The real question is whether it was ethical to post their picture with that comment for the world to see, rather than a) asking them to stop, or b) just reporting it to the organisers.
Why do you feel they deserved a respectful response from her, personally and in private, when they were showing no respect?
Sexual innuendo where they might be overheard by someone was "showing no respect"? Truly, I find that a staggering exaggeration.
Would it? If everyone who was put upon by people being jerks spoke to those jerks they might, if I am being charitable, get a response where the jerks stop being jerks because they didn't realize they were being offensive.
I think you're jumping the shark here. They exchanged sexually laden jokes. This is "being jerks", it makes them "jerks"? As to your estimation of the probability of someone stopping, I find it laughably low. I'm sure as many as 99% of the people I've met at IT conferences would stop whatever they were asked to stop if someone asked them to. Whether they would agree it was "offensive" other than in the eye of one beholder, I don't know. After all, I disagree on that as well.
Personally I think they would react with indignation and anger. They would probably then double down and the whole thing derails.
As implied above, I think your "probably" - implying "> 50%" is out by some two orders of magnitude. Do you live in a city of rude sociopaths, is your esteem of humanity that low, or is it because some off-colour jokes make people "jerks" and thus likely to be sociopaths?
However by calling them out publicly, they lose the advantage of numbers
They had "the advantage of numbers"? Both of them, or just the one who was asked to leave?
and their behavior, and all the nasty behavior from like minded people, is on display for all to see.
"All the nasty behaviour from like minded people"? Hmmm as I'm like minded (though I rarely do innuendo except with close friends), that seems to imply I also indulge in "nasty behaviour". You're not a fundamentalist Christian, right? Just checking.
So the hollow claims of 'There isn't really a problem' can be seen for straw and the actual problem can get some attention.
What problem? One person took offense and went a big - and to my mind unjustifiable - step beyond just reporting it. Few others would have taken offense, which means by the definitions I'm used to, it was not actually "offensive" (yes, I realise A+ uses a different definition, but I don't think that is, or should be, a commonly accepted one).