> So just because you can remove screws more easily you build better shelves?
Yes, with a high probability. Try to put all your screwdrivers away and then try to build a shelf without them. Not only will you need lots of time just for fastening the parts that you cannot spend on thinking on a more optimal layout of the shelf, making the result worse -- you will also judge every layout idea on how hard it will be to build without a screwdriver, instead of judging it on whether it is useful as part of the final shelf.
> You can build bad apps with good tools and good apps with bad tools.
This is a (probably unintentional) strawman. The argument was that tools make the task substantially easier and therefore improve the quality of the end result, not that they make it possible at all.
> Just because it gets easier for the web dev doesn't makes it easier for the user and vice versa.
Again, the argument was that tools make it easier to build a good product, not that tools themselves guarantee a good product. Of course with good tools you can build a bad product, and you can even build it easier than without good tools.