Why does "spyware" only matters for Firefox but not other browsers, considering ~97% of the browser market share is proprietary browsers.

If people cared about privacy majority of users wouldn't use Chrome.

Also what is the point of complaining about spyware when the only viable option is Chrome (and other Chromium based browsers), I trust Mozilla more than any proprietary browser vendor. They collect less data than any of the proprietary browsers. I can actually disable "spyware" using config options. They are not some black box switches that might disable the "spyware" unlike proprietary browsers.