Personalised ads are beside the point. The issue is how they are personalised, namely by building a rich profile of user behaviour based on non-consensual tracking.
It isnt even clear that there's a meaningful sense of 'consent' to what modern ad companies (ie., google, facebook, amazon, increasingly microsoft, etc.) do. There is both an individual harm, but a massive collective arm, to the infrastructure of behavioural tracking that has been built by these companies.
This infrastructure should be, largely, illegal. The technology to end any form of privacy is presently deployed only for ads, but should not be deployed anywhere at all.
Forget fussy debates about morality.
There is a practical threat to society when a few nation-sized corporations operate pipelines of data collection and profile aggregation on every online citizen of the world.
Those profiles represent a massive amount of power, and that power is being let to accumulate in opaque organizations that have no explicit commitment to public benefit and extremely little accountability. That power is not yet being weaponized, but it doesn’t evaporate just because nobody’s using it for leverage or control yet.
The responsible, long-term, practical way to ensure that legitimate governments and the people that constitute them continue to have the power to shape their own society is to make sure that these techniques for accumulating power are dismantled and the already-accumulated power is dissipated.
Yes, we will lose some novelties and baubles in our online life when they can’t track you anymore. Yes, investing new power into government so that it can counter corporate profile-accumulation is dangerous as well.
But the greater danger of inaction against these corporations is that they are already only lightly-accountable and are on the verge of escape from accountability forever if they gain enough power. Modern governments, meanwhile, are comparatively slow and dumb and can still be steered as their dangers become manifest.