I did not envision negative labels as being useful, no. The thumbs down pretty much takes care of it. Nobody wants to know how bad something is. They just want to know how good it is.
Discussion
I guess negative labels are handled as zero weights against the 50% available as nostr:nprofile1qyt8wumn8ghj76rpwejkutnrv9k8vcfwv3jhvtcprdmhxue69uhksctkv4hzucmpd3mxztnyv4mz76twvfhhsqgwwaehxw309ahx7uewd3hkctcpz9mhxue69uhkummnw3ezuamfdejj7qg4waehxw309amk7mnn9e3kzmrkvyhxgetk9uqzp5mwszpl57ekmthxgm9ck0uel64rmz095wt9pp6p7qp7yxkqk6lvctjurf comments here:
https://github.com/nostr-protocol/nips/pull/879#issuecomment-2502210146
If you're broadly positive (i.e. an initial thumbs-up 50%) then you don't want to be dragged below 50%. Similarly for positive labels on a general thumbs-down.
Me likey.