That definition is quite good, I would add that for cruelty to be cruelty the objective of your actions needs to be the cruelty.
Eating meat doesn't fall into that definition, fron my point of view.
You being alive causes a lot of suffering in the world, just because you are alive, you cannot live without doing harm to other living beings.
You draw you line on "I'm not cruel because I go out of my way not to eat meat". There are infinite lines you could draw before and after or in parallel. Someone could say "Ido not walk because I may step on some bug and that would make me cruel, and anyone who walks and thus step on bugs is cruel".
A clear remedy to avoid causing harm to absolutely any other living being is stopping being alive one self. I don't see much people following that route, and considering any living being as cruel would mean that that interpretation of what's cruelty is irrational and faulty. The intention for the suffering to exist is inherent in the cruelty. People need to enjoy that suffering in order to be cruel.
I do not enjoy damage to animals, it's just something inevitable when I eat them. Suffering is not my objective, not the objective of anyone who eats meat, I would assume. So no, they are not being cruel.
From my point of view, if the objective of your actions is not to cause suffering, even if your actions cause suffering, then you are not being cruel. Intention matters here.