It's interesting that so many posters are both adamant that they would think nothing of any sort of body modification on anyone and very cross with anyone who even mentions a negative thought about it. And equating someone privately thinking some tattoos are a bit blurry and wonky and don't look great, with being a homophobe (wtf)?
While other posters are absolutely fine with anything except.....x y and z. And actually what that line is is different for everyone but often seems to include face and neck. And maybe there could be some thought from group a and group b that what is your xyz is different to other people's but the feelings behind it are similar?
Almost no posters are genuinely stating that they would believe a teacher to be less good at their job in any way.
The negativity is almost exclusively limited to 'I might think it looks a bit rubbish' and yet there is quite an energetic defensiveness towards that.
My very good friend is a nurse. She got an (admittedly really rubbish) tattoo on her lower leg as a teen in the 90s. When she did her nurse training and first qualified she was made to wear a skin coloured plaster over it for every shift. Absolutely no visible tattoos were allowed at work. She got it lasered as she was so fed up of the plasters! That was less than 20 years ago. It is really not at all odd that there are associations between 'professional appearance and dress' and expecting tattoos to be discrete or covered up when huge numbers of the experienced workforce were subject to these expectations.
It is absolutely great that times and social mores move on. It would be completely wrong for someone to be poorly judged on anything other than their ability and performance at work. But it's not impossible to understand where people's reticence comes from, nor to share it in some way (as group b do).
(And also, a lot of tattoos are just really not very good!)