It's none of your business why they want to call a referendum, or why anybody would vote as they would, or how they would vote, individually. There may be as many reasons as votes. You will of course vote on it as you please, or not vote, and it's also nobody else's business whether or how you voted, or why.
You are free to announce how you will vote, and why. And you can change your mind afterward, and vote the opposite, without telling anybody.
> It's none of your business why they want to call a referendum
The intentions of politicians are not my business and that is "absolutely elementary civics". That isn't credible.
As to the rest, obvious and irrelevant. When did I make any comment on someone else's right or reasons to vote? I didn't, thank for noticing enough that you refrain from attempting to use it to obscure the issue at hand - your claim about what is my business or not.
Politicians are expected to do what voters are demanding.
They can guess reasons why they think voters want it, and some voters may suggest reasons they think will be persuasive. The pols might offer reasons, too, but they don't really know, so you won't really know either.
And, it doesn't matter. You will vote for, against, or abstain, regardless. People can try to persuade you, but they are not obliged to tell you the truth about their own reasons. The pols, anyway, just want to get elected again and hope that supporting or blocking a referendum vote will do that for them. That is their actual reason. but it doesn't help you any.
If you really believe everybody is telling you the real reasons why they do, promote, or block this or that, I have a bridge to sell you.
I obviously won't believe the SNP from now on, not that I did. You can keep that bridge, perhaps find some less principled pro-independence voters to sell it to.
You are free to announce how you will vote, and why. And you can change your mind afterward, and vote the opposite, without telling anybody.
This is all absolutely elementary civics.