I'm not exposed to this space very often, so maybe you or someone else could give me some context. "Sabotage" is a deliberate effort to ruin/hinder something. Are compiler engineers deliberately hindering the efforts of cryptographers? If yes... is there a reason why? Some long-running feud or something?

Or, through the course of their efforts to make compilers faster/etc, are cryptographers just getting the "short end of the stick" so to speak? Perhaps forgotten about because the number of cryptographers is dwarfed by the number of non-cryptographers? (Or any other explanation that I'm unaware of?)

Any side effect is a side channel. There are always going to be side channels in real code running on real hardware.

Sure you can change your code, compiler, or, or even hardware to account for this but at it's core that is security by obscurity.