Smoking or emitting carbon, or using plastic imposes negative externalities on other people. Second hand smoke causes lung cancer, carbon in the atmosphere leads to climate change, plastic in our environment can cause developmental and reproductive issues. There are reasons to oppose these things that do not include hating people. Some of the tactics may be ineffective or misguided, but this does not mean that everyone who cares about stopping harmful things hates a particular group of people.
I like your idea of putting a price on carbon emissions. Many economists agree that it would be one of the most effective ways to eliminate emissions while allowing the economy to continue to grow [1]. Solutions are there, and they will be employed when the political will for it is built.
Please tell me where it's possible to live in modern society right now without any use of polluting energy. Seems to me like https://knowyourmeme.com/memes/we-should-improve-society-som...
> immediately offsetting a product/service's carbon footprint.
What offsetting do you find acceptable? Most carbon offsets sold are complete bunk, thus costing very little. Stuff we can be sure about (like DAC) are well over 500€/ton right now, implemented now this would be sure to lead to riots, especially since it'll probably affect people with less income the most (relative to their income). A carbon price is a great mechanism, but one this high is (IMHO) unworkable and there needs to be accompanying measures to ensure that the carbon price isn't so low as to be ineffective, not strain citizens to much and not make local industry non-competitive.
If we only implemented it for non-strictly-necessary stuff (like meat, flights, big cars, cars outside rural areas, living and heating a larger dwelling over 18°, ), it would still be very unpopular (and probably lead to riots)
Take carbon-neutrality for example. There's no shortage of people who will rage against flyers, car users, cruise takers, etc, etc as the cause of all carbon related ills in the world. And of course, the complainer's personal use of polluting energy is always objectively correct and morally just. And there are extreme examples like the "Tyre Extinguishers" group, which is clearly just a group of individuals who want to damage others' property under some thin veil of "doing good for the environment".
I say all this as a person that actually does care about the environment, but have not fallen into the easy trap of thinking that hating on others is a solution.
Meaningful central solutions are the answer. If one cares about carbon neutrality, I'd recommend advocating for across-the-board carbon taxation that is directly and honestly tied to the cost of fully and immediately offsetting a product/service's carbon footprint. And then it wouldn't matter one bit if someone wants to take several cruises a year, or drive an "unnecessarily" large car. But the social justification to hate on those people would evaporate, and that would make some other people sad.