I wonder if rather than a true belief in 'democracy', it is a little of the sunk costs fallacy - "we went to the trouble of asking people and they said 'yes', but even though there is no way of making it happen without constitutional crisis, we must plough on!".
There may, of course, be a way of making Brexit not economic suicide a success, but I dunno how (and many finer and more dedicated minds than mine dunno how, either). Current list of (many) of the hurdles here and also on excellent EURef threads.
Anyway, to the OP - I like the idea of tactical voting, any organised action seems worthwhile to me. More generally, I feel like internet grumbling and reading all of the Brexit stuff is insufficient now - twould be nice to engage in some pro EU stuff in RL. To ponder...