If your cryptographic library is not constant time then it is already vulnerable. This new attack is able to target the even previously unaffected constant time

If your cryptographic library is not constant time then it is already vulnerable. This new attack is able to target the even previously unaffected constant time libraries - that's why they call it out specifically in their FAQ, but this is saying that _all_ cryptographic libraries are vulnerable to timing/side channel attacks (when running on processors which don't have these performance features disabled).