This strikes me as the rantings of a CEO who doesn't have any touch with the reality of development. Thanks for the offer, but I wouldn't want to work for you anyway ;)
In all seriousness, I just don't buy that .NET is an amateur language that prevents you from doing certain things. C# is a great, rapidly evolving language with a lot of functional programming features built in. On the other hand (as a developer who used C# for almost 4 years), I felt it gave me more freedom than most other environments. You can even drop down to pointer manipulation in performance critical areas when needed...
And with all the support for asynchronous programming, it makes it easy to write truly scalable web applications with a similar paradigm to Node.js.
And ASP.Net MVC is really nice... if I weren't developing on a Mac and in love with Heroku, I'd probably be using it over Ruby on Rails.
tl;dr; - your rant is only applicable if you are only talking about VBA developers. Modern C# on .NET with ASP.NET MVC is a pretty nice environment.
.NET is a pretty good implementation of a Better Java. It doesn't even suffer from some of the cultural problems of Java. (FooDelegatorHandleFactorySingleton...)
It is a thoroughly corporate ecosystem, though. The vast majority of .NET programmers are work-a-day IT department developers. There is a lot of deference to MS on tools, language features, and libraries. MS developers will tend to wait for MS to incorporate something into the official platform rather than creating open-source projects to fill the same need. (eg. ASP.NET MVC) Even Java is better in this regard. It's hard to imagine something like Clojure emerging from the .NET community.
A lot of .NET hate these last couple days. I consider myself a polyglot, but most of the work I do these days is in .NET. I agree, there's no limitation on what you can do with the languages -- its the frameworks that limit you. Isn't that true with Rails, Django, Struts, and just about any other framework?
As far as languages being a red flag on resumes? I'd argue the more you see, the better. You don't want to see 30 years of C/C++ and nothing else, nor do you want to see someone with 1 year of each language. You want to see passion, dedication, and a genuine desire to learn.
I think the real issue is how much you can make as a .NET developer. Enterprise clients buy things that come in boxes. Rails doesn't come in a box, and it doesn't come with a support contract or a lifecycle agreement. There's something to be said for easy migration from version to version, tested hotfixes, and a fully integrated stack from app code to db server.
As I think about this more, the point may be that .NET is most rewarding for developers at either end of the experience spectrum.
As a very experienced developer, it's easy to get into the low-level framework type features like remoting (and building RealProxies), unsafe code (pointer manipulation), asynchronous programming with io completion ports, etc. All of these features allow experienced developers to create from scratch very powerful abstractions.
In turn, inexperienced developers can easily take advantage of these abstractions to build something quickly. It is this group that the author is referring to (and probably belongs to). Once a member of this group needs to do something outside of the realm of existing re-usable components, it takes a more experienced developer to help.
I think a great first place for him, or anyone, who actually cares about this, would be to make sure to understand the difference between .NET the framework and the .NET languages. The framework has features at many levels of abstractions, and yes, the higher up you get, the less likely you are to see eye to eye with the developers, but there's always a lower level, and at the bottom, you absolutely can fiddle with the bits on a network connection or whatever else he mentions.
In all seriousness, I just don't buy that .NET is an amateur language that prevents you from doing certain things. C# is a great, rapidly evolving language with a lot of functional programming features built in. On the other hand (as a developer who used C# for almost 4 years), I felt it gave me more freedom than most other environments. You can even drop down to pointer manipulation in performance critical areas when needed...
And with all the support for asynchronous programming, it makes it easy to write truly scalable web applications with a similar paradigm to Node.js.
And ASP.Net MVC is really nice... if I weren't developing on a Mac and in love with Heroku, I'd probably be using it over Ruby on Rails.
tl;dr; - your rant is only applicable if you are only talking about VBA developers. Modern C# on .NET with ASP.NET MVC is a pretty nice environment.