I wouldn't say it's necessarily wrong or harmful.

So you say taking advantage of someone who can't say no is alright? Ew.

Sure, never take advantage of someone who is drunk if you are not,

Then don't say whatever happens when one party is drunk is on them. I said scenario above aside because it is indeed a tricky one as one of the 2 still could be against it but unable to voice it and the other could be too drunk to judge and still force it, but that's very difficult to handle imo. Either way it's not as simple as saying "oh whatever happens happens" - no. Even when drunk people can be against something and not want it. Doesn't mean it's smart to get wasted to the point of being inable to say no, but also it's not a free pass.