Oh I don't know where to start.
OP, I pretty much think I agree with you.
I would be pissed off if my DH was very controlling about my hairstyle, and he doesn't really say that much or have much input - however he doesn't really need to, because I know what looks good on me, and I would also take into account what I know his (unspoken) preferences would be. For example, a pixie cut is never going to look good for me, nor is bright red or jet black.
I am also quite chubby at the moment, and he doesn't make me feel bad about my weight.
However, whilst he has no direct input in my hairstyle, and doesn't comment on my weight, he tells me what he thinks looks good on me, clothes-wise, and most of the time I trust his judgement and take it on board, although there are times I tell him I don't care, and wear my own thing anyway.
The same applies to him - I would occasionally comment on his shoes (in fact there have been times I have refused to leave the house with him because of his choice of shoes), and I give constructive feedback about clothes, and sometimes the need to shave (and ear & nose hair), but I don't give him a hard time about weight.
I suppose what I am getting at is the point that we all want to look good for our other half, and take their views into account, without becoming completely subservient to their wishes. I don't think it is controlling to want your other half to look attractive, so long as it is within limits.
I remember many years ago a guy I was going out with at the time turning up with a massive tattoo on his left forearm which he decided to do out of the blue - it was huge, about 10 inches long, and to be honest, although it was his body, his choice, I always thought it looked a bit rough, and finished with him soon after (although tbh, there were plenty of other reasons to contribute to that decision).
If he is determined to have longer hair, can you insist that he gets it properly styled and that he dyes the grey?
Could you also give consideration to changing your nn to delilah? 