Okay I don't necessarily disagree with your support for alternative FOSS browsers, but I don't think what you're talking about is relevant to what I was saying.
First: Firefox is unambiguously Free and Open Source. The majority of its source code is available under the terms of the Mozilla Public License version 2.0[1], which has been approved as a Free Software license by the Free Software Foundation[2] and by the Debian project[3], and as Open Source by the Open Source Initiative[4] (pick your favorite authority) and the rest is available under similar Free and Open Source licenses -- primarily Apache-2.0 and LGPL 3.0 & 2.1, as well as a number of other licenses for various third-party components. You can see this for yourself if you open Firefox and navigate to about:license in the URL bar.
Second: yes, the Mozilla Foundation does not grant a license to use their trademarks as part of this source code licensing.[5] This has caused trouble for various organizations in the past, as you've pointed out in the LWN article you linked, but does not contradict Firefox's status as Free and Open Source. Many other projects have similar terms, such as (to pick a recent infamous example) the Rust Foundation,[6] and many established Free and/or Open Source licenses have clauses that explicitly state they do not grant the rights to any trademarks, such as GPL v3 (via an optional term, see Section 7 "Additional Terms", list element e: "Declining to grant rights under trademark law for use of some trade names, trademarks, or service marks;").[7]
Moreover, the specific issue at the heart of the article you link is no longer an issue and hasn't been since Mozilla clarified their stance on use of their trademarks in 2007.[8] That is 18 years ago. The Debian project hasn't shipped Firefox under the name "Iceweasel" since 2016.[9] This is ancient history. (The Linux source tree was still being managed by BitKeeper at the time that LWN article was written!)
And more to my original point: yes, it is embarrassing to see that Mozilla is following in MS & Googles' footsteps here and integrating LLMs into their browsers (albeit with a "kill switch" permanent total opt-out, which no other big player seems to be shipping[10]), I don't see how that contradicts my claim that Mozilla doesn't ship bad features to make money off me. What is that you propose about me that these new features would entail selling? My data? Targeted Advertisements? A subscription for a feature that used to be free? This isn't any of those, it's an attempt (misguided, perhaps) to grow Firefox's popularity. That's not exploitation of users.
You can choose Pale Moon or GNU IceCat or the Tor Borwser (all three forked from Firefox, BTW, because it's open source[11][12][13]) or Epiphany or Lynx or even Brendan Eich's "Chromium if it was Anti-Woke" over Firefox, I'm not gonna try to change your mind, but you should do that for informed reasons. Mozilla Firefox remains the largest open source non-Chromium browser project; and in an era where WHATWG's "living" web standards dictate that only institutions are capable of producing performant and conformant web browsers, that invaluable engineering work should not be squandered. Mozilla do a lot of good for us.
(Also, one final note: Mozilla makes more than just Firefox. A VPN, an Email mask service, Thunderbird, Bugzilla, SpiderMonkey, pdf.js, MDN; and they still contribute heavily to their spin-off projects SeaMonkey [formerly the Mozilla Application Suite] and the Rust Programming Language, as well as plenty of third party FOSS projects. Almost all of these are the same or better than the peer products produced by their competitors.)
[1] https://github.com/mozilla-firefox/firefox/blob/main/toolkit/content/license.html
[2] https://www.gnu.org/licenses/license-list.html#MPL-2.0
[3] https://lists.debian.org/debian-legal/2007/07/msg00197.html
[4] https://opensource.org/license/MPL-2.0
[5] https://github.com/mozilla-firefox/firefox/blob/main/LICENSE
[6] https://rustfoundation.org/policy/rust-trademark-policy/
[7] https://www.gnu.org/licenses/gpl-3.0.en.html
[8] https://web.archive.org/web/20110817064956/http://apcmag.com/the_stoush_over_linux_distributions_using_the_firefox_trademark.htm
[9] https://www.pcworld.com/article/419749/iceweasel-will-be-renamed-firefox-as-relations-between-debian-and-mozilla-thaw.html
[10] https://www.techradar.com/computing/firefox-responds-to-ai-backlash-by-promising-a-kill-switch-for-turning-off-controversial-new-features
[11] https://www.palemoon.org/
[12] https://icecatbrowser.org/index.html
[13] https://support.torproject.org/tor-browser/getting-started/about-tor-browser/