linguistics - How can we distinguish between statives and gerunds in English?

If the "-ing" suffix is not used in
stative verbs then why do we
use the "-ing" suffix with stative verbs
in gerunds? For example:
loving, believing, knowing, hating
etc.; with these verbs why do we
use "-ing"? When I googled, I found the book Reference to
Abstract Objects in
Discourse by Nicholas
Asher which says "No stative
verbs have gerund
forms" so I was totally confused: are stative verbs used as gerunds or not?