If you read the article, it's more of an "it depends" answer.
Most phones have safety mechanisms built in to them to protect from things like overcharging or overheating during fast charging. They will also default to a low power charging state if it doesn't detect the correct signal from the charger.
There is a very rare possibility that a charger may not be grounded correctly and that's why it's recommended to stick with big brands if you're going with a 3rd party charger.
Unfortunately the battery temp limits are often too high and let the heat at go really high which shortens the lifespan of the battery. If I let my Pixel fast charge as it pleases, I'd have drastically reduced battery capacity today. Instead I use USB-A to USB-C cables and older chargers to limit the charging current and therefore heat.
Answer is absolutely. If they don't follow USB-PD protocol correctly they can damage the battery or the charging circuitry in the device. If they are made with poor quality parts they can also die prematurely and cause voltage spikes when they do which can again, damage the battery and charging circuitry.
Some people may argue that you should never buy any other charger besides the one that the manufacturer supplies with the device. This is not a good argument though because most of the time the charger that the manufacturer supplied is an off the shelf charger itself, just rebranded to their own brand name. Most of the time it's a reputable brand which is why these tend to be more reliable. So basically sticking with a reputable brand is about the same level of safety if not more safe than the one that came with it.
Note that a reputable brand is not those ones that you buy at a gas station or street shop, or the ones that you buy dirt cheap on Amazon. Those are examples of chargers you probably want to avoid.
Also while we're on the subject of chargers this same concept does apply to docking stations for laptops, phones, and PC gaming handhelds, because these docks also have USB-PD chips in them as well, and the shitty clone versions can easily malfunction and damage your laptop, phone, or gaming handheld. The solution is the same as with the chargers, try to only use docking stations from reputable well-known brands.
Just don’t buy the cheap pieces of crap at the checkout counter at 7Eleven, or the ones from China that are 25¢ per dozen on Amazon, and you’re probably okay. Get a recognized brand one on sale or closeout etc.
Same advice I gave to Nintendo Switch users when they ask about chargers that are safe for the Switch, unsurprising it's applicable for all chargers in general.