This has nothing to do with accepting or not accepting people for who they are

to you. you do not see this as someone's self expression because you do not value it. That is OK if you don't have anything similar you'd like to express yourself with, but that doesn't mean other people do not. Would you not agree that some people identify with their hair, tattoos, style of clothing, etc? Piercings can be the same way

Some people think cilantro tastes awful, and I don't understand those people on that point either.

You don't understand that some people have a genetic mutation that causes their taste buds to be more sensitive to the flavour compounds in cilantro, including Aldehyde?

What is hard to understand?

Aldehydes are a flavour compound in cilantro that in small doses gives a fresh, light and vibrant taste. Aldehydes are also present in the soap making process, various other cleaning agents, as well as being released by certain insects.

If you taste a lot of these specific Aldehydes, you will taste soap. But cilantro doesn't contain enough Aldehyde for most people to notice any fowl tastes.

That is, unless you are an X-man with mutant taste buds.

Their taste buds pick up on the Aldehydes, and therefore cilantrotastes like soapy stink bugs.

It doesn't mean I don't accept them for who they are.

[...]

looks gross.

You don't get to claim you accept people for who they are, then call them or aspects of their appearance "gross".

If you truly believed that people can have preferences we don't agree with, then you would keep your mouth shut when you see a piercing you don't like, but that clearly they like having.

Accepting people starts with learning that if you can't say anything nice, don't say anything at all.