Back in a more adult age, the way that this was handled was "We've benefited from our past collaboration, but we believe a new direction is needed going forward."
For some reason--COVID brain rot, poorly-socialized people coming online, general increase in viciousness in the population, who knows!--people have forgotten the utility and purpose of boring polite manners and communication.
For some reason--COVID brain rot, poorly-socialized people coming online, general increase in viciousness in the population, who knows!--people have forgotten the utility and purpose of boring polite manners and communication.