That's not how I see it.
SNP proposed a motion, as was their right, and Labour refused to engage with the SNP beforehand to sort a joint position. Reality is that the SNP and Starmer don't have a joint position on Gaza as the SNP thinks what Israel are doing is wrong and want them to stop immediately, and have been prepared to say so publicly for months now.
Clearly lots of people won't have been paying close attention, but this idiocy did achieve a few things: it publicised the SNP's position, in case people had missed it; it showed up Labour as not really having a position, in case people had missed it; and it exposed Starmer as willing to engage in bullying tactics in order to get his way and scupper a vote.
Scuppering debates and votes is not a good look. How many of the millions of Labour voters who are already disgusted by the Labour Party position on Gaza are now even more angry about it? Starmer is a hapless politician, and yesterday was a good example of that.
As for the SNP being 'bitchslapped', what happened yesterday will have done them no harm at all among the electorate. Yesterday's debacle is a good example of how it is possible to lose by winning the wrong way. It seems to be something of a Starmer speciality.