"Baldur's Gate: subtitle" would have been the ethically proper way to go here
I don't recall any ethics debates over Fallout 3's name, etc. Lots of game / movie / book series have used numbers without being a direct continuation of previous entries.
Of all the franchises Raze could have picked he went with Fallout.

I would have taken Final Fantasy or Dragon Quest for example instead as both drive his point home more closely.
In all seriousness, Fallout's fandom are slightly divided in that one side of the aisle believes 1, 2 and New Vegas are true Fallouts and superior to 3 and 4 in terms of writing and exploration whereas the other is more likely to have been introduced to the series via 3. I would not recommend that Baldur's Gate go down this path.
The reason some people are upset on here is because there have been statements to the effect that fan expectations are "soaring through to the roof" (made without due clarification), that Swen wants to do his own thing yada yada and because next to nothing has been shown of BG3 since.. uh, June? If WoTC is trying to pull a bait-and-switch here with a product called BG3 that has absolutely nothing to do with the previous games (by the way ToB was supposed to be BG3 if I'm not mistaken so there you have it, three mainline titles that revolve around Bhaal and the Bhaalspawn) I think I have the right to know as a prospective customer. It is also my duty to let everyone know what is going on in that case. If it's meant to be a clean break then do a reboot and call it Baldur's Gate instead. This isn't about making a direct sequel to the Bhaalspawn story but whether the legacy of the previous games will be honored as far as lore, history, writing etc.
So, what are you saying then? I'd still argue the same point as Raze. Plenty of franchises have continuations in their title, when the first story is even completely finished. All of this sounds like a personal opinion/expectation, and you want everyone to have the same opinion as you.
It's a '3' because it adds more to that universe, bringing in more stories to the fold. I really don't see why, what or where your upset is coming from.
Alright, can I take you word at face value? Are you affiliated with Larian in any official capacity?