That would be an another incredible display of stupidity and lack of insight on Musks part. Folding to a mere threat is worse than any physical attack for starlink as a defense contractor. Russia almost certainly lacks the ability to significantly damage the constellation, while losses would be covered by insurance and other means. Forcing Putin into action would either call his bluff or show his hand. The world would see a demonstration of Russian ant satellite technology and be able to adapt. A kinetic approach would probably go Kessler syndrome and even if not, it receive very severe international condemnation and pushback from everyone with a space program including China and India. A electronic attack would get a workaround eventually and still piss off everyone who operates in that hemisphere.