[staticassertion]

> a security bug in them that one time?

More than one time.

> a cryptographic performance enhancement feature

It's very rarely used.

> Did we blacklist OpenSSL's binaries after Heartbleed?

No, but lots of companies have since migrated away. OpenSSL was harder to move away from because there weren't as obvious drop-in replacements. Blocking a syscall that you never actually used is simple and effective.