Why do we say “open” and “closed”? Why is one in present tense and the other in past tense?

Question

Edit: to clarify, I mean when shops have a sign that says “open” versus “closed”. Why is it not “opened/closed” or “open/close”?

In: Other

Answer 1

I open it, I close it.

It is open, it is closed.

It was open. It was closed.

Tense isn’t the issue.