That's true, but then we don't have a dictator. And you could always vote Monster Raving Looney as a placeholder until a better party comes along. But you've already often got the choice of the big two plus Green, Lib Dem, UKIP, BNP, Brexit, TUSC or some other flavour of socialist - plus various other choices in Scotland and Wales. If you can't find one of those to go for, then perhaps there's no pleasing you.
As for the specific case the OP raised of the referendum - then it was a pure binary choice. If you're happy (enough) with EU membership, vote remain - if not vote leave. It's a pure binary choice. Obviously there could be various flavours of leave, but if you think the risk of getting one of those you don't like is too high, then again, you vote remain.
If you don't vote - then you get whatever the winning side voted for.