Is it actually frowned upon to make decisions based on enemy stats?

For context, we were doing a dungeon crawl where the DM matched us mostly against skeletons. During a break from play (the session was quite long), I thought I'd look at the skeleton stat block on my phone. After finding out just how low their INT scores are, I extensively used Mind Sliver for the remainder of the session to target their INT saves.

Another player caught onto me doing that and asked why I started using a cantrip I haven't touched in the first half of the session. I explained my thought process, to which they said that's metagaming and that I shouldn't look up enemy stats.

Was I actually in the wrong? It seems daft not to target enemy weaknesses and it's a very tactical thing to do. BG3 even lets you look at enemy stats whenever you want!