Charitably?

Someone who believes that because we can't tell some kinds of good speech from some kinds of bad speech, we should give up trying.

It makes about as much sense as eating a moldy blue cheese once, enjoying it[1], and deciding that from now on, you won't turn your nose at eating whatever putrescent, rotting garbage is put in front of you, regardless of how sick it makes you.

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Less charitably?

Someone who can very much tell the difference between good and bad speech, but is cynically promoting bad speech, for selfish reasons.

[1] Despite a general understanding that moldy food is not suitable for eating.