> Am I the only one agrees with the author that generics probably do more harm than good
It's really the same debate as 'Dynamic' vs 'Static' languages, since without generics your code is relying on runtime type checking in anything remotely complex, thus is effectively a dynamic language.
Personally, I'm of the opinion that people that don't like static typing only feel that way because they've only used the shitty implementations in Java or C#.
Regardless, This is a religious war that has raged for decades, and isn't likely to be answered anytime soon. The answer really comes down to "It Depends". I fall firmly in the 'static typing is good' camp, mainly because I have hard evidence to back up my opinion that it results in significantly fewer defects.
(Specifically, very clear reports from from issue tracking systems showing our defect rate in production dropping by 90% (!!!) when we switched from Groovy to Scala, with a notable increase in productivity).
Some of the developers complained, since they had to learn knew tools. But being professionals, they learned new tools and were better off for it.
Now while I'm an extremist religious zealot about proper static typing being the one true way, I'm quite mindful that, for many developers, that tasks they are working on just aren't complex enough for it to make much of a difference in practice - they are able to test all edge cases and deploy stable software to production, just with a little more runtime testing than they'd otherwise need.
Some languages - such as Go, or pre-enlightenment Java, do not implement Generics, and thus require runtime casting in many cases. In these languages, there's still a degree of compile time checking, just not as thorough as it should be. As with dynamic languages, they can work with no perceived issues for projects up to a certain size and provide a reasonable halfway point. Beyond this, you're going to hit a wall.
As to your argument that Generics do "More harm"? I'd strongly disagree. If you're unfamiliar with the gotchas generics introduce (i.e. Variance can be a mindfuck), then they can seem difficult and problematic. But like any other professional tool, once you've gotten over the learning curve you're more productive with it than without.
tl;dr If I wanted to bang a few pieces of wood together, I'd feel comfortable using a Hammer. the learning curve small, and I can connect those two pieces of wood in no time.
My Uncle is a carpenter. As a professional carpenter, he bangs pieces of wood together all day long, every day, for his entire career. As such, a nailgun is a more appropriate tool. While being more complex to use and having a steeper learning curve, he's a professional, and uses a professional tool to do a professional job. Occasionally he might want to bang some quick project together in his shed, and getting out the nailgun is overkill, so he uses a hammer for the odd thing here and there.
I'm a professional programmer. I use professional tools, even if they have a steeper learning curve and might be more complex. Occasionally I want to whip up a quick script, so will just hack it together in Python.