In no way, it's a personal choice as far as I'm concerned. Both my parents are meat eaters. In my teens I felt "heavy" every time I had eaten meat, in other words I didn't feel well, and that's what made me first cut down on meat, for years I did eat fish, but then decided that I could do without. I would never advice people to become a vegetarian, it's something you have to decide for yourself, and you can't make the change in a couple of days, that would be an unwise thing to do. Anyway, lamb, fish and foul are preferable to red meat (acid forming) and if red meat should be eaten, then only occassionally.
Cruelty to animals, I think we all know when that happens, when there is needless suffering, and the adrenalin produced because of stress is bad for humans.