> Any instance of selective enforcement being necessary is ipso facto evidence of a bad law.

All laws are in some degree bad; perfect laws do not exist.

Some laws are useful and produce more good than harm in the concrete situation in which they exist.

Should laws be improved where possible? Yes. Does the need for selective enforcement indicate a problem? Yes. Does it provide sufficient information to determine the precise form of a better law to replace the one it shows a problem with? Very rarely.