As someone who never was a dub (but has sympathy for those who were/are) I'm sorry to have to tell you this from my perspective in the UK.
Dubs who come to the door are generally regarded in the same light as the cold-callers who want you to switch energy-providers or try to sell you over-priced domestic goods. In other words, a nuisance to be dismissed politely (or not, depending on your mood). About the same level as 'harmless' e-mail spammers, not quite so bad as the West African spammers who want to give me £50m. About the same as flies/midges who pester you on a summer evening.
Dubs like to think that they are hated and persecuted but in fact the opposite of love is not hatred but apathy.
Most people I know are completely apathetic about Dubs. Those who know anything about them, or who have engaged with them (only to rapidly disengage when they realise Dubs still teach Adam was created about 6,000 years ago) tend to have bemused pity for them. Those who know nothing about them tend to lump them in with the other American weirdo religions they've seen on TV (Westboro Baptists, Mormons, First White Southern Baptist Latter Day Church of Mississippi, United Snake Handlers of West Virginia in The Name of the Nazarene, Reformed Disciples of the Holy Mount etc. etc.)
So no, the Dubs are not despised. At best they are tolerated with a bemused smile, probably politely because we are Brits, after all, but with as little understanding or interest as Buddhists who want to explain why their particular brand of Buddhism is best. Complete disinterest, in other words.
Sorry, Dubs, I'm not interested enough to hate, despise or persecute you.
PS: Edited to say I made up some of those weirdo religions - but I'm sure there are others just as weird I didn't think of.