Can a co-author prevent me from submitting our joint paper to any journal except the one he prefers?

Jointly authored papers require permission from all authors. If he is a co-author and you can't convince him, then you are pretty much stuck. Editors will expect it.

And fighting with your PI is probably not the wisest career move.

It is a different story if the PI isn't one of the authors, but that only applies to the first point above, not the second. The "we" in your question wasn't completely clear about who is included.

It may not be too strong to say that a good letter of recommendation from your PI is one of the most valuable things you get out of a post doc. It lets you move on and get away from improper behavior. Winning a battle, but losing a war is sub-optimal.

I'd suggest you analyze your options in a more strategic way rather than going heads-on against the PI:

• First, is there a way to clarify things with the PI, maybe reach some kind of compromise? Ask them to clarify exactly what they mean by "politically incorrect" or "too slow". They might actually have reasonable conditions, in which case you could try to find a good journal which suits both of you.
• If this doesn't work, you need to identify exactly the obstacle. Normally the PI should tell you, but apparently this might involve this other paper that they published. If so, is there a way to smooth things up? Maybe by re-writing some parts of your paper in some kind of diplomatic way, like acknowledging previous findings and presenting the present work as a contribution which goes beyond them, as opposed to bluntly confronting them. Scientific progress often involves healthy debate of ideas, it shouldn't involve conflict of egos.
• You mentioned another colleague and also "a good interdisciplinary collaboration", so it seems that the work involves multiple co-authors right? Where do these co-authors stand on the issue? Could they be convinced to support your cause? Would some of them be in a better position than you to convince the PI, or at least to put a bit of pressure on them? If the work is really good, I would expect the other colleagues to also be eager to publish it in a good journal. And if your PI is blocking the paper for selfish reasons, their position is going to be weak in front of the other colleagues.

Here the resolution/answer:

I spoke to the second PI/co-author alone. He agreed that he thought the data were excellent, and suggested he speak to the other co-author alone, recommending I choose which journal to submit to. This was definitely the right move.

Unfortunately, it turned out that there was a different motive: the first PI wanted to switch to a different project and so needed to show that he had one publication out from our project. He gave comments on the paper to change straight away although on holiday, and I was told that he would not accept any discipline-specific journal because they would not be out in time for his application.

I replied again to the second PI saying this was not right, and he apologised for the situation again and said the first PI would not change his mind so I would have to choose whether to make a formal complaint or accept the compromise of journal (not Frontiers but not a discipline-specific journal). I’ve accepted the compromise of journal.

Essentially: I spoke to the second PI alone, he agreed I could decide where to submit and agreed with what I had suggested, he spoke to the first PI, the first PI changed his position from Frontiers but wouldn’t accept a discipline-specific journal. We are proceeding with this. The next step would have been to make a formal complaint.