Support techs do not have access to insider industry information. They deal with dozens of region-blocked game support issues a day, and in 95% of cases that block was placed by the publisher. The tech is likely just using that term out of assumption and familiarity.
I’m not saying it’s impossible that Sony are the culprit, but a random support reply to an individual is not how we’d find out. It’s happened before that a Valve official puts out a correction to something support says.
They should have been part of the original restriction and it was noticed when the restriction was put in place for Tsushima. This was noticed and executed independently by Valve.