I understand that you were addressing the safety issue. But to make a case based on that issue is to knock down a straw horse. A lot of otherwise bad behaviors can be made safe by the world's standards.
If you are a Bible believing Christian then you understand that we are called to a higher standard. The standard for the temple was spelled out in exacting detail in the OT. The standard for our human temples is spelled out pretty clearly too in DNA. Tattoos, sexual perversion, drugs that are gateways to hardcore addiction and the like didn't make the cut.
Alleging legalism is a diversionary argument. As Paul says, many things are allowed but that doesn't make them beneficial. Even if a tattoo is allowable, clearly it is not beneficial. It affects your testimony and is a stumbling block for your brother. Not engaging in that which you know is a stumbling block is also a Biblical command. Or is that command just more quaint Biblical legalism? I think not.