The Dursleys:

[aceworker]

No: HPFGUIDX 167390

Why complicate the Dursley's reactions and abscribe any motivation to 
them aside from fear?

Why can't the Durlsey's just be people who are afraid of what they 
don't understand and therefore do what sadly most people do with new 
and frightening things; attempt to crush the idea.

Most likely the Dursley's have never had a positive experience with 
magic. Name one canon incident in which something positive happended 
to them that involved magic. 

>From their POV magic can do nothing but harm them. It killed Petunia's 
sister for Merlin'sake.

I always thought that JKR was always just trying to portray the 
Dursley's as fearful and materialisitic people. JKR finds this 
contemptable as 'courage' she has said is her highest value.