"Medicare for All will diminish healthcare access and quality." Medicare for ALL will diminish healthcare ACCESS and quality (as for quality, no it won't either). Yeah right. Also, Joe Biden absolute loathes medicare for all and recently the democrats considered walking back on the public option.
The green new deal will not destroy capitalism and the free market. Again, Joe Biden doesn't support the green new deal.
"Socialism does not work, and it has killed millions (from marxism leninism mostly but whatever)." This is approximately the 131245th time I've heard this lazy argument. Joe Biden first of all is a neoliberal capitalist, not a socialist, and most of Bernie's policies have worked extraordinarily well in other countries.
No democratic presidential candidate advocates for open borders. No one.
Defunding the police simply means reallocating some of the funds from the massively overblown police budget into social services like mental health, education, etc. This way, we can meaningfully address the root cause of crime, therefore meaning the need for police would be diminished.