I'm pretty accepting and never had any strong opinions on it.
The more I think about it, though, and the more of them I see, I think that they are really ugly and a bad idea 99% of the time. Very rarely do they add something of value and often they make the person uglier.
I do have some respect for ritualised tattoos. Like sailor tattoos that signify certain milestones like crossing the equator or tribal tattoos that signify kinship, marital status or things like that. However, this doesn't exist for most tattoo havers.