Correct me if I'm wrong: I think that a wound that is bleeding is a wound that's, at least in part, being protected from infection by 'internal positive pressur

Correct me if I'm wrong: I think that a wound that is bleeding is a wound that's, at least in part, being protected from infection by 'internal positive pressure'. My grandpa taught me that; to let wounds bleed freely for a while, if possible, to reduce the chance of infection. I wonder how valid that is.