Let me try to spin this into a male perspective for you, even without his side of it or the countless details you've left out.

Argument of logic vs emotion. Think about it if you told someone 2+2=4 yet they kept being adamant and angry that it is actually 5.

this time I refused to back down

You just keep shouting 5 over and over.

I needed him to let me know where I stood in his future.

He's dating you, he wants to be with you. That is his 4 and all anyone can ever know. You are demanding a road map from him. Why? How? Men don't meticulously daydream plan their futures.

I asked him if we should take space to think about it

You threatened to break up with him if he didn't bow to your will (5). That is manipulative as fuck.

He was all over the place.

No shit, he loves you but you opened his eyes to what a future with you would be - manipulation, threats, and arguments over literally nothing.

I do think ignoring is wrong (I would've broken up with you) and immature but he was likely trying to weigh the pros and cons of being with you. He may have even interpreted your threats as an actual breakup/space request. Or even simply shut down from the stress you were intentionally inflicting as men often do.