> common for a wannabe Bitcoin millionaires to run mining software on computers and electricity they do not own or pay for
Define “common” and provide sources for your claims please.
Monero Javascript miners are common to this day.
They're an easy way to donate to people in places where it is hard to transfer money. What exactly is the argument you are making here? Presumably the people running those things are definitely paying for their power one way or the other.
They get delivered through ads and sites directly in order to steal further resources from unsuspecting site visitors.
The days when this was either widespread or not blocked by mainstream browsers are behind us. At this point it is mostly scaremongering for no good reason.
With speculation on currency (it's the primary use of Bitcoin) and theft - the latter less so, given the very high centralization of hashing power, but it was and still is common for a wannabe Bitcoin millionaires to run mining software on computers and electricity they do not own or pay for.