I would say the equivalent to a cot is a puppy pen not a crate. Especially as crate are used with adults dogs as well very often.

I tend to disagree with crates because I want my dog to learn how to behave around the house and to be able to trust him as much as I can (within reasonable limits) and Id rather adapt my house to make it safe than confine the dog in a cage.
But then I dont agree much with any animals in cages, which is why I wouldnt want to have rabbits or hamsters or the like. Its a personal ethical standpoint to some extent.

And yes anything can be cruel if used wrongly however there is more of a risk so to speak with crates...of course you could choose to beat up your dog with a toy but thats a bit extreme...whilst with crates the limits are not obvious and not everyone agrees..is 3 hours in a crate ok? but 4 hours not? or should 2 hours be a maximum? should it be different at night? where is the distinction between good for the dog and sheer convenience of the owner? There is more room for problems and dogs (most) dont express as much as humans their distress and displeasure...

I just dont agree with animals in a cage I suppose and would not feel comfortable restraining my dog this way.

So crates will not form part of my dog's training and routine, although I do provide him with a safe den but which remains opens at all times.

Its a personal choice and responsibility at the end of the day.