You don’t get sick from the bacteria, you get sick from their excretions
Their excretions are on the outer surface (prove this to yourself by letting a piece of meat rot and see that it gets slimy on the outside)
Therefore removing the excretions from the outer surface can make a piece of meat safer. Washing seems like it would do that

It can seem very compelling, it can seem like it ought to be true. It used to be commonly recommended.

[–] otp@sh.itjust.works 2 points 3 days ago

I think 1 is inaccurate -- bacteria themselves (not just their excretions) can make you sick.

I think the idea is that the bacteria are supposed to be too cold to multiply and make their excretions by the time you cook the meat (and thus kill them off), so unless the meat is already spoiled, cooking alone would be fine.