It does not matter. Any ideology can be followed blindly to one’s ruin. Nationalism is common, but there are others.

"The LGBTQIA flag obviously"

"It's clearly the national flag"

the kind that flag shaggers shag

I’d say what matters is whether it matters to you. What difference does it make in the outcome?

Flags overwhelmingly represent nations, groups considering themselves nations, that were nations or have some kind of individual governmental status.

If you asked 100 people to imagine a particular flag to attach to that statue, 95% of them are going to be current, unrecognized, or former states.

Why could it not mean multiple flags at once?

It is universal. The flag, the state, the man. Details don't matter.