Don't doubt you. You spend more time on the range than probably any three people here combined and are exceptionally credible.
Lot of people buy a "Glock" because it's a "Glock" and they either don't know how to shoot and/or they buy some crap Russian ammo and their Glock jams.
My Gen 4 Glock 19 has ran perfectly. Over 1,000 rounds and it still shoots like day one. I only shoot quality ammo and I have eight mags that I rotate through.
For the record, I shoot with getoffmylawn on occasion. I've never seen him post anything that he didn't believe other than some funny things to stir the pot and this may not be one of them. I don't know. That being said, I don't shoot with glock shooters typically, so I can't back up what he says.