[veridies]

> In case of taxing A and C, C's freedom as a group would be compromised.

True. That's why targeted taxes (eg carbon taxing) are often a good idea. However, if we as a society vote to do things that seriously harm a subset of society, then we as a society are partially responsible for that harm.

> In case of taxing only A, the cost would be prohibitive and could discourage A from wanting to do its thing in the first place.

I think it's entirely reasonable to price externalities into the cost of an action.