Tactically voting for them to keep the Tories out is an entirely different thing from choosing to vote for them because you don't like Labour right now
Sure, but the thing is most of us will be in this position one way or the other. What I find frustrating about the arguments going on between Lib Dem and Labour supporters is that most of the time they are missing one crucial bit of data; where they live. This one piece of info should be the deciding factor in how we all vote, but it's hardly ever mentioned. We should just forget about theoretical preferences and stop bickering over details. If Labour are most likely to beat the Tory candidate then vote Labour, if the Lib Dems are most likely then vote Lib Dem, same for Greens, Plaid, SNP etc. In 3-way or even 4-way seats it's tougher but a bit of research can normally clear things up. In rock solid safe seats then a) be absolutely certain it is a rock solid safe seat in these strange times and then b) vote your preference.
I know that there will be occasional exceptions to this rule, but apply common sense and weigh options against the likely alternative.
I doubt that the remain/referendum parties will get their acts together to cooperate so we are going to have to do it for them by hammering home the message that our shitty electoral system means we can't be precious or purist, we have to be practical.