You wouldn't ask for that information in that way.

Most places would say because it's faster or why would you use anything else? Not give you any company history.

Ask who makes technical decisions. Or what debt structure they have. Not why they choose aws over azure.

Assuming you're not desperate for work you're interviewing them just as much as they are you. Perfectly valid.

And you clearly misunderstood what they meant by technical debt.

Your interviewing them but in this case it was a pointless question asked at the wrong time with no possibility of anything of value coming from it.

This place uses php. It's in the job description (either that or the parent had no knowledge of what the company did before the interview) so the discovery should have happened earlier in the process.

By asking that question in that way the parent poster is signaling that he is modern but at the same time saying the company isn't modern by phrasing it that way. Wanting to understand how a company makes decisions is valid. Making judgement statements through questions is not valid.

And yes misunderstood company for technical debt reference.

Now I get you, completely fair. I think that would mostly come down to tone though.

The whole democratic voting for implementation and architecture decisions drives me crazy.

Am I being irrational?

I just want somebody to make a decision, and if it is wrong, we learn, and try something else.