You’re right that they either never learned what 1st-2nd-3rd world really means, or they forgot what they were taught in history class. Unfortunately it still is the main term to refer to poor countries even though it’s incorrect. Language seems to be biased towards the common meaning over the technically correct meaning.

No one really uses that word in its Cold War context anymore. It’s the common term for “developing countries” and the like.

“Waste heat” is a relative term.

The amount of underpaid/unpaid overtime I’ve heard of is terrible. At this point I will always ask if someone gets paid 1.5x if they’re hourly working overtime, or if they’re classed as salary exempt from OT pay. The former is blatantly illegal yet still happens often enough, while the latter can be legal but is usually taken advantage of with no compensated days.