That's called scabbing.
There's a legal definition of a strike, union and employment vs contractor. Just like there's a legal definition for prisoners and torture.
You can't get the rights associated with an unionized strike (anti scab laws) without the consequences of being unionized (dues for instance).
"Scab" is a hate term that has been used to justify violence against so-called scabs. Epithets for gays have served a similar purpose in the past and are now considered to say more about the speaker than the target.
"Worker" is treating people as resources and not people