Distracting errors are annoying, but because the errors do not interfere with your ability to understand them, I wouldn't bring it up. Because this is a social exchange, I don't really think it's appropriate to bring up mechanics. In the case of professional and academic settings, I would absolutely mention it. (I don't think it's snotty to be annoyed by lazy writing. I'm a professional grammando and my friends will periodically use dreadful grammar just to see my English Teacher Death Twitch. I just don't think it's as important to everyone as it is to people like us. If you can easily understand what they're saying, then asking for something closer to SEE is a personal preference and not really something that you should dictate.)
If the errors get to the point where understanding is difficult, then I do think you can bring it up. I'm not a gamer, so I'm not sure how you'd make an aside, but something like, "Can you please give your posts a quick once-over before you send them? I think your autocorrect is on the fritz. I wasn't sure what you meant by 'raffling goop' at first. It took me a minute to realize you meant 'grappling hook." I guess that if the errors are distracting enough that they really take you out of the scene, you could say something similar. I'd blame autocorrect and use a specific example of something that confused you.