The perfectionist's paradox

EDIT: ADDED Oct. 16 2018: As Karim Zahidi notes in the first comment below, I made an elementary logical error in thinking that (1) is evidence for (2). So I have crossed out the original mistake like this below. But I still think the argument after that step may work: so now the argument just starts from (2) as a supposedly plausible claim, instead of trying to justify (2) via (1).

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This might sound initially like a too-clever undergrad ‘gotcha’ paradox. However, I think that at least for some folks who have perfectionist tendencies, the following is experienced as a genuine difficulty in their lives.

The following strikes me as plausible:

  (1) It’s OK to make some mistakes.

If (1) is true, then it seems the following should be true as well, since it’s just a restricted version of (1):

  (2) It’s morally OK to make some moral mistakes.

But

  (3) Making a moral mistake is doing something morally impermissible,

and

  (4) if something is morally OK, then it is morally permissible.

And (2)-(4) logically entail

  (C) It’s morally permissible to do some morally impermissible things.

And (C) looks like a contradiction.

(For all I know this is already out there somewhere, but it was not on the interesting list of paradoxes of deontic logic in the Stanford Encyclopedia.)