While this might be true, it's at least half a lie – SPD, Grüne and SED could have initiated proceedings anytime targeting one of AfD's state chapters in Saarland, Mecklenburg-Vorpommern, Lower-Saxony, Bremen, Hamburg, or Berlin (2016-2023). They didn't. You should explain why their reasons to not do it have been valid, while not being valid reasons for non-leftist parties. Also, SPD isn't even trying to convince CDU/CSU right now... they benefit from the Brandmauer, because without AfD, there would be a clear majority for non-left parties and no one would need a coalition with the SPD.
> note that this is merely a request for an examination; the final decision rests with the Federal Constitutional Court.
Again, true, but also half a lie. It's not merely a request in the sense that there's no risk associated with it. The backlash of a failure to ban the AfD would be ginormous - the situation would be much worse than it is right now. That - and the fact that SPD and Green benefit from the Brandmauer - is the reason why even center left parties don't really move forward with a ban.