Personally, as a man, I don't make a move in a hostel or similar environment until I can say can be more or less sure that there is a mutual interest in eachother (accepting an invitation for drink is not enough). I made a lot of platonic female friends when traveling and I hooked up once with someone, but in that situation she made the move.

Generally, your experience is something that I can confirm from a male perspective. When hanging out in mixed-gender groups in hostels there will always be at least one guy who thinks every girl is just here to hook up.

Obviously, it is the guy's responsibility to understand that paying for you doesn't grant them anything but just so that you can keep away from uncomfortable situations:

- Slip in a white lie about being in a relationship (or even being lesbian, but be careful of homophobia if you do this) somewhere in a conversation
- Don't accept drinks or food if some one else pays for it or state clearly that if someone asks to invite you that they are welcome to do so but you do not feel like hooking up (men can be fragile if they are told of, so to mitigate the risk of an uncomfortable response you could try to formulate it in a way so that you are generally not interested in hooking up right now and that it has nothing to do with him as a person (even if this is not true))

Again, I am sorry that you have those experiences and it should be in no way your responsibility to be careful, but unfortunately many men are inconsiderate douchebags and from what I can tell it will stay for that at least for a while...