Blue collars sometimes defined as low skill job, often a manual labor. I would define it a bit another way - it is job which requires low training (at least up front), so people who can not afford university go to this job, or people who get into complicated situation or lost their previous job, basically when you tight on the budget and you need money right now, and you need to start now or ASAP and you don't have time, or better say privilege, to spent 5 years in university.
In my article I gave following definition:
By that definition then still 💯 lol 😂