> Yes, real world mining is a serious offender, but that doesn’t exempt crypto mining.

Agreed, they have essentially nothing in common apart from the name.

> Have one look at one photograph of a crypto mining farm for one second and this will be obvious to anyone.

Why? You can get pretty bad pictures of eg factory farming, too; still that doesn't mean people will stop eating factory farmed meat.

> On the point of double spend - collusion in bitcoin mining is very possible and decentralization is not as strong as claimed. There are tons of studies about this.

The pdf you linked says nothing about double spending.