You know who should put ALT tags for the visually impaired on their embedded graphics? Everyone, obviously, because wouldn't you want to be included if you were visually impaired?
Writers and aspiring writers have another compelling reason to ALT tag their posts, though--you can get AMAZING skill practice by trying to effectively convey memes and visual jokes in text.
Don't phone it in, either. Do your best. Try to make it POP. Yes, it seems awkward, but it'll get better--and so will you.