The same argument used by retired people who vote against school bonds. "I don't have any kids in school. Why should I have to pay."
Many examples of this (il)logic.
Of course, on the other extreme we have tobacco taxed to provide health care for children.
If eavesdropping serves a valid public need, there is no good reason that the public, in general, should not share the burden.
But, that is a big "IF" - i.e. that eavesdropping serves a valid public need.