To be fair, float point equality is often a red flag and often deserves a double-take (even if the result is, yes, it's correct).
A comment like "exact equality is deliberate here and valid because XYX and important for meeting performance requirements ABC" would help, unless it's a major part of the system, in which case the colleague should know that already.
And on their part, a check in with you for "hey, I don't understand why this equality is valid" would be better than assuming it's wrong and changing it.
