The reason they say is because it's 'patronising' and 'gendered'.
I wonder what the old Geordies think about that?
(Actually is 'old Geordies' patronising and gendered?
In the NW the term 'luv' has long been used, particularly by my generation, as an informal friendly tag on the end of a greeting or sentence.
( Although I've never quite got used to 'Queen'.)
There'll no doubt be older Punters on here dotted around the land, who may have used other popular regional words such as 'Duck', 'Hen', 'Hinnie', 'My Lover', 'Babes', 'Boyo', 'Treasure'.
After a lifetime of using these friendly terms sometimes it's not easy to stop, even if I wanted to.
I know context and tone are important, but generally speaking they're used and received in the friendly manner intended, particularly in the regions where the term is common.
Maybe the exception to these terms is 'Dear'?
Yes it can be used in a friendly way, but very often misused as sarcasm or patronising.
Sybil from Faulty Towers comes to mind.

What d' yer reckon chuck?