[love2read]

Who cares what you think of someone else’s qualifications?

It’s just someone quoting someone to help ground their position.

What if it was a journalist writing about a security vulnerability then a programmer quoting them, would that count then?

[jmull]

If it doesn't matter, why did the previous poster mention them?

It's pretty clearly a type of argument called an "appeal to authority", where an authority is cited to add credibility to a position. It's usually considered a pretty weak form of argument, but it can be effective. So the credibility of the cited authority is relevant.