I think you are conflating two different things here. I am not debating the first paragraph on how companies treat users but I really doubt the 2nd para.

Not using "open source" doesn't mean what you are implying. There are a lot of considerations companies go through on selecting to work on OSS or not.

That said, the quoted example is confusing at best. Companies are made of people and people have biases. You never know what kind of bias or consideration the hiring manager had in mind. Normally, for me if someone makes a statement which I don't agree with - I do make an effort to ask "Why?". I don't simply walk off because someone has a different opinion. But maybe, that is my idea of getting hired - understanding what and why of things I might end up doing.