People can always object when they want to and I can agree some people become involved in politics at a point where they become too appalled to stay out of it, or it impacts them badly.
I only have anecdotal evidence for this too - I became so appalled at the racist and far right that I joined Stand Up To Racism and do various activities with them. Others recently joined feel the same, or joined earlier for similar reasons, some have always been activists. Some folk decide not to campaign as directly but may volunteer for such as food banks, refugee charities to help the issue that upsets them. There are also similar options for those on different points of the political spectrum.
However, I cannot agree this takes the form of signing upto discussion sites such as here, Reddit, digital spy (probably showing my age!) to join in debate on the opposite side of long running threads you wouldn’t agree with - it’s not an effective objecting tool. Activist groups would recommend many other things to do to get your view out there - social media like Insta, fb, X etc if you can’t join anything in person.
You may not be aware but people are on their longer running preferred threads like this to feel they’re not alone, to discuss matters of joint interest - not to campaign and try to change another poster’s viewpoint. There are individual threads to argue on that come up regularly though.
Anyway, as you’re keen to make folk know how bad labour is there’s a long running thread for that too where you can find your tribe.