The bottom line is that the Tories got in because there was no realistic alternative, demonstrated by millions of formerly loyal Labour voters voting for whichever other party they felt most comfortable with, or Tory because Labour had not got its act together about Brexit, mismanaged by Corbyn to the nth, and though it grates on me to say this, because they believed in Boris.
I resent your point about voting for other parties than the Tories PippaZ, I can’t speak for anybody else but where I live there was a viable alternative - but see it as a protest vote if you will- ultimately it doesn’t matter, because it happened, and if nothing else it sent the clearest signal possible that Corbyn and crew had to go, and the Labour Party had to change.
I do think the COVID situation would be managed very differently by a Labour administration now, but we weren’t in that position in March when it hit.