I mean; they cause no harm unless you are a farmer or something, do they?
Another thing I saw at a park: The crows surrounded a swan. One would pick at the swan's butt. When the swan turned around, another would do it. It looked like they bullied the swan for entertainment.
That's not so bad! That alone makes them better than pigeons, which simply poop on everything (sidewalks, cars, people, other pigeons) regardless of any personal animosity or lack thereof.
On the subject of cruelty in animals:
> '[...] humanity may come to terms with the dwarf, the troll and even the orc, terrifying though all these may have proved to be at times, and you know why this is, Drumknott?'
> The secretary carefully folded the duster he had been using and looked at the ceiling. 'I would venture to suggest, my lord, that in their violence we recognize ourselves?'
> 'Oh, well done, Drumknott, I shall make a cynic of you yet! Predators respect other predators, do they not? They may perhaps even respect the prey: the lion may lie down with the lamb, even if only the lion is likely to get up again, but the lion will not lie down with the rat. [...]'
-- Snuff by Terry Pratchet