is an e-learning platform a type of social media platform ?

I don't think so - and I speak as a person who just got an MS in Interactive Media from an online program. E-learning platforms are less for opinions (although they are used for them), and more for assignments, lectures, etc. You hand in your work, you might have a discussion, you see what the next assignment is, you listen to (or watch) the lecture, that sort of thing.

Social media platforms, instead, are for discussions and opinions but there are few 'assignments'. While aa blog might feel like a lecture at times, there's nobody grading you for reading it.

Consider the meat world. We don't equate classrooms with parties or with people hanging around and talking.

hmm.Thank you Jespah. I think it's clear to me now