You're arguing that the actions of individuals have no impact on the collective actions of humanity, the sum of 8 billion individuals.
Similarly, you probably never had a conversation where someone said "Gee, I'll stop burning fossil fuels now!" But when you use public transportation, or patronize businesses on foot, policy makers are motivated to continue supporting such options. Not for you personally, but for you and others like you.
I prefer to donate time. I'm now president of one local non-profit (in addition to my paying job), and a regular participant in another. Sometimes I'll donate supplies that we need, but never money.
If a time comes when I have little time and a lot of money, maybe I'll switch. Donors are necessary. But I know that we need hands more than dollars.
Why do you think BP produces emissions? They may be evil, but it's not out of malice, it's for profit. People, like the 26 million residents of Australia, pay BP to give them more fossil fuels.
A top-down response, where governments just outlaw all extraction and burning of fossil fuels, would be a lovely, quick solution to the climate crisis. By all means, try and make that happen, but I wouldn't hold my breath.
One thing you can do today to make an impact is to adjust your lifestyle to give less money to the fossil fuel industry. An individual carbon footprint is small compared with a company, just like the money they give to BP is relatively small, when compared with their total profits. But when you add up all the customers, their money adds up to the revenue of the industry, and their carbon footprints add up to the footprints of the relevant companies.
That's valid.
I do think it's reasonable to have an interest in what kind of development is approved and funded. I wouldn't support developers who wanted to build McMansions, and luxury condos are less appealing than affordable housing. I expect there could be some extreme, unrealistic case in which you too might oppose a specific development, even if it was high density.
Aesthetic appeal (and yes, NIMBYism) is what kept a lot of small cities in North America, including mine, from being replaced by strip malls.
Of course, this line of reasoning could be continued to oppose anything and everything.
Pointing out that the proposed development would be out of place does not make you a hypocrite. Maybe you and any like-minded neighbors can explain your viewpoint, emphasizing that you would be happy with a smaller apartment building.
It may be that in a few decades, such structures will not look so out of place in your neighborhood. Developers seem to think there's a demand. You live in a desirable location.
I can commiserate. I'm in a similar area, with a mix of single family homes, duplexes, and small apartments, a few blocks from a walkable downtown. I don't think a 6 story building would be aesthetically pleasing next to the 2-3 story structures near me.
With that said, I emailed my representatives, and hope to attend the city meeting in support of a new zoning plan allowing for more apartments and businesses, without parking minimums in my neighborhood.
Maybe it will even happen before California HSR!