Most Helpful Guy
It really depends on the guy and his intentions at that point in his life. It may just be that he liked some of the girls photography pics on Instagram. It could also be that he think she's attractive and either wants to just be in her presence or he wants to flirt. For Facebook obviously the guy may just know the girl and likes her pics in a completely platonic way. But realistically lots of guys follow girls and like their pics as a way to flirt. I personality agree with you and don't see myself following a girl or liking their pic just because I think she's hot while I'm in a relationship. I've seen this wisdom several times and it's interesting how most guys respond in a defensive way as if they are personally being accused. I have a feeling you won't get a thoughtful answer from most on this topic.