J states that people who want to minimize bacteria in their homes should use antibacterial cleaning products.
K notes that those products can be harmful because the bacteria they dont kill will become resistant, so people should not use these products.
Both of these arguments rely on the idea that the products kill many bacteria. J would not think you should use them if they failed to kill bacteria, and while K notes that they do not kill ALL bacteria, but by talking about the bacteria that survive, she implies that the cleaners are effective at killing at least some bacteria.
So, we know they agree that the cleaners kill some household bacteria.