There are those who permit it. How about banning all stores that sell bagels with cream cheese and lox, because there are many who don't eat fish with cheese...
Nobody just "permits" it.
The OU recommends a certain bedika. If this bedika is positive for bugs there is no cleaning process available. Supposedly this bedika will show infestation 99% of the time.
For this reason the OU doesn't allow rasperries and blackberries in facilities with their hechsher.