just like what jaka said that happens in relationships in general
I think I understand your point, because tbh I hate it too when people get in a relationship, any relationship may it be long distance or online or real life, and they're not even serious about it, like they say they just do it for fun so they flirt with people and have a fling for less than a month or less than a year
and that is more common in online relationships because first, you don't really see each other in real life so it would be easier to get over because you won't be interacting that much anyway, second it's easier to 'fool' people because you just need to be a smooth talker, third it's hard to tell if you are serious or not because well, it's an online relationship, and there are a lot of other reasons that makes people not take online relationships seriously
like you, I also hate it when people get all lovey dovey then it ends up to nothing, it doesn't only happen in online relationships, it also happens in real life too
and also like what jaka said, it's not only the girls who get hurt, sometimes it's the girls who fool around
and yes getting in an online relationship sucks, because you don't get any of the good part, like hugging holding hands etc. and when you two breakup it sucks more because of the time you wasted and your heart feels like it's just been played and then left to break into a million pieces
don't generalize because there are some people who are serious in online/long distance relationships but of course the percentage of an online relationship to work out is much less than that in real life