What’s good about block politics is that it fixes the mathematical problem with single-vote. You get the best of multi-party systems (you can get nuanced representation) and of two-party systems (you have the highest possible chance of avoiding the most disastrous outcomes, of voting out the worst of the fachos—assuming that the party you hate the most is in the opposite block).
In Sweden the parties on the nominal left hate block politics and each other (and for good reason because they’ve treated each other horribly). They don’t wanna govern together, which means that a vote for them is not a reliable vote against the far right.
Unfortunately, there’s no alternative except to vote for one of them and hope that they can sober up for three seconds and that it’ll be enough to keep the brownshirts off the throne for four more years. That’s unlikely since they’ve spent more of the campaign trail time pulling each other’s hair and breaking each other’s hearts than finding common ground.
They’ve spent more of their time joining the right on the race to the bottom of climate action delay, selling out our kurds, and alienating our immigrant population. Instead of staving off the right, they rush to become like the right.