"Poor billion dollar company" cannot possibly be a slur in an industry that requires $2 billion in investment (and rising!) to make each subsequent product. Maybe if the product were a luxury good that the world could do without, but it's not, and we cannot.
You don't need to trust anything except that left to their own devices, those greedy pharma companies will price as efficiently as possible in order to maximize revenues. Despite this revenue maximization, the industry as a whole is nearly uninvestable.
Any deviation from the optimal pricing will reduce their overall revenues, which will obviously make the industry even less investable.
In an R&D heavy sector means they will no longer make new products, i.e. no new breakthrough medications that you or I or our parents or children may need.
Sure, I doubt Pfizer et al will just outright stop selling medications to France. Far more likely they will both reduce US prices and raise EU+ prices, but this still ultimately results in fewer drugs for fewer people today, and definitely much slower innovation toward new drugs by virtue of having less cash on hand and much worse expected ROI.
You do not need "trust" whatsoever, this is just basic logic.
If you want to understand how Americans should actually reduce drug prices, you can start to get an idea here: https://news.ycombinator.com/item?id=46933520