I don't think it's unreasonable to expect your employer to buy your tools, but I also think the best developers will eventually have their own tools for their personal projects - once they have a little extra money post-college.
In the post, his dad says, "Yeah, I’ve got about $6000 of my own tools." The tools provided for me at work probably run closer to $15,000 and probably only lasts a year or two before another payment needs to be made for a new version (vs. hardware tools that last decades, as long as they are any good). Also, developers often "buy their own tools" in the form of library books, technological equipment, and other investments that are more difficult to have employers pay for. Finally, there is much more variety in developer tools - starting with Microsoft vs. open source, and including source control, CI, and so much more - which really needs to be selected from by the person making the business decisions, usually the employer (unless you are freelance). So I think it's reasonable to not own your own tools for your day job.
At the same time, putting time aside for personal projects is key to becoming one of the best developers, and part of that investment is buying the tools for your own projects.