Was, he said it a long time ago. He has said a lot of things that sounded kind of far-fetched and paranoid at the time, but which were later demonstrated to be true, so "Stallman was right" is reappraising the past statement.

I understand what you mean, but he’s still saying it and he never stopped.

Lots of people are saying some of those things now, but Stallman was saying them decades ago. It's not differentiating or meaningful to say "A is right" if B-E are saying the same thing at the same time.

Let’s just say Stallman was and is still in the process of being right