One word: profit.

Although it is a little more complicated than that. It is one of humanity's traits that they don't want to accept they were wrong.
Nobody can deny the big pumps that ethereum had in the past which has given a lot of profit to many people and worst of all has given hope of future profits to a lot more who are now bag holders. They do not want to accept that they were wrong about this whole thing being a sham even though ETH has gotten dumped so much in the past 5 years without being capable of seeing its ATH against bitcoin ever again.