Dr. Wildberger is notorious for having non-standard ideas about mathematics, including not believing in irrational numbers, etc. The ire that Pythagoreans had towards irrational numbers is still alive and well in Australia!

I recommend checking out his Youtube Channels. He is an excellent lecturer, who is able to communicate complex ideas in a very clear way. The cherry on the top is that it is so fun to listen to his nonstandard ideas, which he can and does advicate for in a very powerful way.

Even if you believe in irrational numbers (as I do!) it is good to examine and re-examine the things you are cock-sure about.