Geoengineering is Earth version of whitening makeups
Aerosol injection and makeups are on the same principle, mineral particles distributed on surface promote reflection.
It's also a quick fix that doesn't require commitments to switch healthier lifestyle to improve base condition.
But it is a fix.
If you have a cavity, and you go to the dentist, nobody says "Oh, that's cheating, you took the easy way out."
If it works, it works, if we can actually reverse all the symptoms (mind, properly, not half-assed in a way that just shuffles some under the bed), then you have fixed the problem, kudos.
This is like those religious fitness types who think it doesn't count unless you have never touched a carb or sat down on a chair, it's your psychological issue, if a person is satisfied with the results, that's what matters.
Not against the technology development itself, but it's a fix temporary, symptomatic treatment at best. It does not address the root cause.
In the analogy makeup, it needs to be cleansed every day and applied everday again to keep effectiveness and avoid adverse effect to the skin. Symptomatic treatment needs upkeep once employed while the root cause is still there. And in case of aerosol injectiom even after the root cause is resolved, retrieval of those particles from atmosphete is much difficult and costly. There are countless technology that seemed reasonal fix at the moment later revealed to be of harm due to oversight.
Is my pov doom and gloom? Maybe. However there are tremendous uncertainty, and the global nature of aerosol injection its effect on existing system is hard to predict, if not impossible. New technology develoment needs to come with development of its harm reduction / retrieval method (as in cleanser analogy).
It's a fix that buys us time and technology that let's us fix it better over time.
If we can fix it perfectly once our tech gets better, then no harm, no foul. We can use the time to develop technologies that make our energy not polluting.
Buying time gives us the options we need to grow into a species that can actually handle our power, which we are absolutely not now. The alternative is definitely worse.