First, a latte is not comparable to a brewed coffee. Dunkin’s latte is above average at 250mg/20oz, but their Starbucks’ brewed coffee is actually substantially stronger, containing 410mg/20oz (!!!). Their blonde roast is sitting at 475mg/20oz.
Second, while Dunkin is above average in many regards, I wouldn’t call it particularly “extreme”. That terminology is a consequence of the objectives of the website. The figure you originally cited (95mg) is for a generic 8oz cup of coffee. Multiplying that by 2.5 yields 237.5mg/20oz, which isn’t all that much lower than Dunkin’s 270mg.
As you pointed out, energy drinks traditionally have a lower caffeine content than coffee. This is starting to change with newer offerings in the space, but I have no disagreement there.
Once again, the caffeine content of the lemonade isn’t the problem, but rather the insane number of reports of people buying it without knowing that it is caffeinated.
To be fair, they generally advertise it as regular lemonade and market it with an unlimited refill deal. I've drank 3 green teas before while at a Starbucks over a few hours. These lemonades contain far more caffeine than a similar sized cup of coffee. This is the second death linked to it now.
It's not wild to think you might drink 3 refills of a lemonade during a visit to a restaurant, but it is unusual to think you might drink 3 times the maximum recommended dose of caffeine doing so.
Edit: back of the napkin math. 3 large lemonades = 12.3 cups of coffee.
Serving size is one lemonade, they offer refills, and the fda recommendation is 400mg caffeine, charged lemonades have up to 260mg. The concentration of caffeine has no impact on this because the fact is you are expected to drink at least one whole charged lemonade, that's a serving size. If you were to drink 20 oz of coffee, you'd be drinking medically significant amounts of caffeine as well, but most people don't do that in one sitting! And they have plenty of advance warning not to.
They will rightfully lose these wrongful death lawsuits, and simping for a corporation will do nothing to stop that. I doubt at this point it will have a significant impact on PR perception of companies or suing, especially in these spaces.
20oz of coffee is not "medically significant amounts" of caffeine. It's just a lot of caffeine. Dangerous levels are significantly higher. It wouldn't even be uncomfortable if you aren't particularly sensitive to caffeine.
The FDA doesn't say "if you drink more than 400mg of caffeine you will die," it says "taking under 400mg / day is not generally believed to be associated with ill effects for healthy adults." There is a stark difference between a threshold where a health agency is saying "everything under here is OK" (they would aim low to err on the side of caution) and a threshold where "everything above here is dangerous."