Yes, but that doesn't mean it's all reliable, does it?

That wasn't my argument though, was it? I was making a very specific refutation of the statement "Your mind was changed by a personal experience. This is something that is undeniably an unreliable method for determining truth." Since everything ever experience is personal experience, it therefore follows that personal experience is not inherently unreliable at all, unless of course you take a very extreme view of epistemological nihilism, which is another can of worms with it's own set of problems.

As far as we can tell, 'spiritual' means nothing. It's entirely subject
to an individual's experiences and how they describe them. I've never
experienced anything 'spiritual' because I've never felt the need to
describe anything as 'spiritual'. It's vague, meaningless language
that's used to serve whatever purpose the individual wishes. How does
this make my disbelief unjustified?

Who's 'we'? Billions of people today, and the vast majority of humans to exist in history intuitively know what spiritual means. A couple million products of modern liberalism not understanding what 'spiritual' means doesn't negate the fact that >98% of humans to ever exist on some level understand it.

And I did not say your disbelief is unjustified. I actually said *you are* justified in not believing it if you personally haven't had any experiences.