Google and TikTok may seem free, but every click and scroll you make gets packaged into a "user profile" and sold to advertisers. Take Facebook, for example—it makes about $50 per user per year just from their data. In the internet age, if you're not paying for the product, you are the product.
They offer services and pleasure that we certainly get but on the other hand they get benefits in terms of traffic and of course the privacy that we have for now is actually very difficult so in this case we cannot deny that there is a price that is appropriate or that must be paid when we really want something.
It is a business that is sometimes not realized for them, especially lay people who sometimes say that everything in the form of free services like this without conditions but in the end we realize that apart from our privacy, we also end up becoming an object because after all for now we as internet users and users of several applications like the ones you mentioned have become an object for their benefit in the business that is done so even though we consider some search engines or social media free but in the end we ourselves are the ones who provide benefits for the business they are developing.
The thing that people need to realize is that they are not doing something shady, not something illegal. Just because you are sharing your own stuff online, doesn't mean they shouldn't use it, they are free to use whatever you upload there. It could be your thoughts and ideas on twitter, it could be your food or images on Instagram, or it could be some sort of short videos on tiktok, doesn't matter.
These companies are offering you a free service like you said which means they need to make money some way, so marketing is the only way. The only illegal part, would be anything like Cambridge Analytica type of thing, if anyone abuses it then it is going to be a trouble and will shape the future of the world to highest bidder, that is the only bad.
The practise of sharing information and sharing opinion over social media can be considered as a norm in the present society. It is written in the nature of the internet that everything that we post online is open for the public domain; they are free to access, utilise or even misuse. Any service that operates for free generally has working strategies on how the it will continue to run, the data we give out is precious. Until such a time that its usage reaches a point where it is detrimental to society, it should not be a cause for concern. That which is worrying is the use of such data for a negative agenda or if it is altered in any way without permission. Thus, openness of the managers who handle such information is something that defines how the context of the digital world will evolve.