I personally wouldn't take anything as that to me, is wrong and classes as theft. I would also be concerned about being caught doing this.
I do really understand why people do take stuff though. What is the point in leaving something that is going to become rubble and forgotten, when if taken the item gets to live on. I think there is actually something quite beautiful in that, I just wouldn't do it myself.
My issue is that if you start creating arguments that it is okay sometimes, you blur the line more. And this concerns me as I feel it could give people who take things for the wrong reasons and personal gain, i.e. to sell on etc. an excuse to justify their actions.
I guess for me, I would never knock anyone for taking anything if they felt really strongly about preserving the history or the item. But I worry that if we normalise it being okay too much, it gives a platform for those who take for the "wrong" reasons to defend themselves for selling things on for self profit which I really don't agree with. Self profit is absolutely far more acceptable in dire situations of course especially in current times economically, but it's those who go with intent to cause disruption, mainly in places that actually are not abandoned, that I have the problem with.
It's a tricky debate to have in the community but I don't really see the harm on the whole. If you are happy to take something and accept that if caught there could be consequences and you are doing it for the right reasons then there is no harm in it I suppose?