Plutoids make them sound like other less appealing things that end in "-oid".
They're just following the standard Latin nomenclature, where -oid means 'the likeness of'. The same as planetoid (likeness a planet) and asteroid (likeness a star). IMO, it's a very distinguishing position Pluto is now in, it is the very object for which all future 'plutoids' will be named after.
Given the origin and all I could see "planetoids" in the spirit of scaling up from asteroids since they are "like" planets, it's just that I recall at one point earlier in their discussion they had referred to them as "plutons".
Not that it really matters all that much to me ... What's in a name? That which we call a rose by any other name would smell as sweet.
But considering the origin of the name - suggested by an English schoolgirl I understand - with possibly Disney and not Roman mythology on the brain - and meshing apparently with the initials of Percival Lowell - Lowell observatory and all that tracked it down and adopted it - I just think it seems an odd nod to history to preserve the "pluto-ness" of it at all now it's decided it doesn't meet the new concocted definition.
Ultimately I suppose calling them plutoids now is at least a way of tossing the Pluto-purists a bone - so to speak.
Interestingly Pluto the non-anthropomorphised Disney dog - as opposed to Goofy - the lower IQ dog that wears clothes - though he too first appeared in 1930 too didn't acquired his name until 1931 - the year after Venetia Phair made her suggestion in tribute to Pluto, Roman God of the underworld.
The origin of Disney Pluto from Wikipedia (fwtw):