Is there a word or phrase defining a bad faith argument that something is not worth doing?

I feel like there is a logical fallacy or bad faith argument for a claim that something is pointless, worthless, or has no effect:

"Contact your congresspeople!"

"There's no point. It doesn't do anything."

I'm having trouble locating the actual term, though.

Defeatism

[Merriam Webster]

• an attitude of accepting, expecting, or being resigned to defeat

Or somewhat related fatalism

[Merriam Webster]

• (belief in) a doctrine that events are fixed in advance so that human beings are powerless to change them

Negativism seems like a good fit.

• "The practice or habit of being skeptical, critical, or pessimistic, especially toward the views or suggestions of others." TFD

• "An attitude of mind marked by skepticism especially about nearly everything affirmed by others" MW

• negativist (noun)

• negativistic (adj) e.g. a negativistic behaviour