It's the way many folk learn to play, on many different instruments. It's the way children learn many things - 'monkey see, monkey do' - no offence intended - I learn/ed a heck of a lot that way, and not just music.
It works until there's a situation where there's no opportunity for someone to show you what to do, but the music is available. Then you're stuck! Either fluff it, or look as though you can't really hack it!
At least with snare, there's only rhythm to contend with, unlike most other instruments, where there's notes (the actual pitch) as well, on the lines and spaces. So learning rhythm reading for snare is simplified. And worth looking at. You'll look at some patterns and think - ah, I already play that, that's what it looks like on paper. What's to lose?
There's nothing wrong with you, it's just that so far, you've been lucky to have someone to show you, or access to youtube, etc., but to be a good muso, the capability to read enhances your chances, and particularly just on snare, it's not onerous. Go for it!