I did a little googling on ISA, they come out of a Trotskyist org called CWI that split in 2019. The main faction eventually reformed into ISA, while the splitting faction accused the remainers of ignoring trade union agitation, and not incorporating class analysis in their work on advancing gender equality and LGBTQ rights.

Could be nothing, could be made-up, or the main faction could be following the wrecker playbook :shrug-outta-hecks: who can say