@ Don Jefe
TL;DR - you are correct, but that doesn't mean it's not a chronically broken system.
True, but such legal defences cost money. A lot of money. Even if a defendant wins a legal proceeding, that is rarely the end as there are often appeals, further sapping time and money. That is why only about 5% of such cases ever get to trial.
A patent does indeed allow "you to legally pursue someone infringing on your patent", as you say. The unfortunate part is that, by-and-large, that is all that is required to start pursing someone.
Simply owning a patent allows you to send threatening letters demanding settlement or cessation, which is the way most patent actions seem to proceed. A patent may not be truly valid until ruled on by a court but the problem is that such a ruling does not have to occur before sending demands to all and sundry.
In essence, the job - and expense (greatly inflated) - of rigorously examining a patent claim is left to the defendant, rather than the body tasked with assessing the application in the first place (the USPTO) or the party asserting that their invention is both unique and eligible for protection by a patent (the patent applicant).
For someone being targeted by a patent claim, the first step is to engage specialists to review the patent and assess its validity. Then they must do an infringement assessment, analysing the allegedly infringing device/software/concept/shape/colour/facial-expression to see if it does actually infringe upon the patent.
Depending on the patent and product, that process could well cost over $10K* - not an insignificant sum for a small business or start-up. If you don't intend to capitulate straight-away, that process is necessary as without it you could be found to be 'wilfully infringing', vastly inflating any potential settlement.
It's worth noting that, as there is no legal framework around making such demands, the patent holder doesn't need to specify what action of the product infringes or which claim in the patent is being infringed. That only needs to happen once litigation has been started and the alleged infringer is already knee-deep in legal bills.
So a patent holder can, at minimal cost, and with no legal requirements, send your company a letter demanding licensing payment for some alleged infringement. To even assess the validity of the threat, you have to fork-over ~$10K.
I accept that the current state is that court is where patents are truly validated, but that arrangement is broken as it allows, and has lead to, a great proliferation of entities extorting money from anyone and everyone. The small companies just can't afford to take it to the courts and the larger companies that could afford to test the validity of a claim in court overwhelmingly appear to choose not to because someone has calculated that it is not financially worth it and that settling is cheap. 95% of claims end without the patent ever being tested in court.
So, while patents must be tested in court to properly determine their validity, that, in practice seldom happens and the result is that patents are largely assumed to be valid and treated as if they are.