Considering them to be ugly is indeed subjective and entirely your prerogative. Considering them to be trams, however, is objectively wrong and just makes you look silly
Whilst I agree the 777s are trains not trams I would go as far to suggest that they do have an interior tram like feel.
I took the opportunity to have a look at one when put on display at Birkenhead North last year and definitely felt they had more of an interior affinity with modern tram design rather than modern train design
Inside they certainly feel more "tramish" along the lines of Metrolink or modern Blackpool due to the articulated open connections between cars.
The predominantly yellow livery also perpetuates the tram connection. Being so close to Manchester which had yellow Metrolink cars.
My view is that Merseyrail should have used the opportunity with the 777s to introduce a new distinctive livery.