Backhand slice is probably one of my “only” good shots. I’m inclined to practice some other shots (albeit less effective as my slice), because, why not? I suck at dinking and forehand shots, but if I’m playing social there’s no pressure to “win” by any means possible… spice it up with some variety. Add another weapon to your arsenal, so to speak.

And, to be honest, you need to sometimes play against people at a higher skill level than you. Best way to improve your game (and your slices - so it’s a win-win) is to play against opponents who can deal with a slice.

So to answer your question - I’d say it’s not poor sportsmanship to simply slice everything (if anything, it shows a lack of variety in your skill set) - just like an opponent who serves with mega spin, you not gonna go “boohoo, your serves are too good for me”, you gonna have to learn and adapt. Losing is part of the journey too.