Feeling very humiliated and very dull after my first interview, how do I overcome this?

I (21M) just had my very first interview for a volunteering position today, and honestly, I feel absolutely horrible and completely defeated. It was for a volunteer/trainee position at a local OP shop (thrift store). I was particularly drawn to this kind of place because their mission seemed to be about training people with "no experience" and helping them build skills. My background is a bit different – I've never had to work before due to coming from a well-off family, so my resume is completely empty. While that's been my reality, I've recently realized the importance of gaining real-world experience and contributing, not exactly or only for financial reasons, but to grow as a person. On top of this, I've been dealing with pretty severe social anxiety and isolation for the past few years, and honestly, my main reason for seeking this opportunity was to finally get some "exposure therapy" to the real world and try to overcome these mental health challenges.

During the interview, the interviewer started asking me directly about my past few years – why I haven't volunteered or worked before. He wasn't overtly yelling or insulting me, but he kind of just laid out the "facts" of my inactivity and questioned why I hadn't done anything to help myself earlier. It felt like he was humiliating me in front of others (there were other people present, not just me and him) for not being "the average human" who has been consistently doing things. I didn't have a good answer for him because, honestly, being confronted and reminded of my errors and mistakes of life, especially my struggles with anxiety and isolation, in that moment and in front of a group, left me completely flustered and confused.

I left feeling so bad, so low, and completely mortified. It felt incredibly unfair, especially given my specific reasons for being there – to finally start, to learn, and to grow. Towards the end, he asked if I wanted to join their waitlist by filling out an application form. I'm torn about what to do.

My questions are:

• Is this kind of interview experience (being questioned/shamed about past inactivity, especially when a place says "no experience needed") normal, especially for volunteer/entry-level roles?
• Should I still join their waitlist and fill out the form, or is this a massive red flag that I should run from? Might be outta topic but the volunteers there were not in the best mood and looked really uninterested indicating a bad work environment?
• I still really want to gain exposure and experience to help with my social anxiety and to move forward in life. Should I keep looking for other volunteering opportunities, or has this experience proved that I'm not ready?

Any advice or shared experiences would be hugely appreciated. I just feel so defeated right now.