Wonder if they just have a bunch of cheap chromebooks that they use to keep everything separated.
It can be done easily with each user having his own browser (Chrome, FFox, Edge, Brave, Opera, ...) on the same machine
or, for clearer difference and avoiding surprises, with separate virtual machines installed for each.
That part is the least problem imho.
(However, I'm still shocked about these findings, since we don't talk here about the usual shitposters).