Yeah this person is just making things up, the majority are not H1Bs. Also, there's this popular idea (usually on places like reddit) that H1Bs at big tech are paid "slave labor wages" because "They can't leave". This is just not true, they get the same salary and stock ranges as everyone else.

Source: was H1B (worked at a couple of big N, but not Amazon) until I got my green card (and then citizenship).