Likely no real reason anymore...just a classification...an historical artifact like so many other things
The Wikipedia description of fundamental focres is typical:
and reading it suggests
but this is not very accurate.... they should say "everyday" or 'typical' particle physics.
In studying high energy collisions for example,such as at CERN, gravity isn't usually simportant....BUT
'particle physics' in neutron stars and black holes, for example, and with electron, neutron, and quark degeneracies gravity is EVERYTHING...