Wikipedia is not he bible. Several examples can reveal wiki`s errors.
I think, phase inversion are identical to a 180deg phase shift for sinusoidal (periodic) signals only.
However, ther are also non-periodic applications.
The article talks about the phase (and very important delays) caused by speaker placement and speaker polarity. A speaker that is close to you produces sounds before another speaker that is farther away so the outputs do not cancel properly when they have a 180 degrees phase difference.
Clipping has nothing to do with phase or polarity. Clipping occurs when an output level is attempting to go higher than is possible. A transistor without negative feedback produces severe distortion at higher levels (but not clipping).