I'm in a similar boat. That's just how a lot of people I know communicate. Sure they have other ways to communicate, but they don't want to.
You can ask said email/sms/whatever. If the communication matters, you should have them anyway. If not, then those persons are not that important.
> There's a large number of people on Facebook that I interact with that I don't have email / sms / whatever for.
There you go ! Here is one of the other reasons that I stated before. Not the "those people I can only reach through facebook" bullshit.
Oh, I'd agree they're "not that important" but that doesn't mean "...and therefore I should cut them out of my life."
> Not the "those people I can only reach through facebook" bullshit.
It's not "bullshit" just because you disagree.
I'm in a similar boat. That's just how a lot of people I know communicate. Sure they have other ways to communicate, but they don't want to.