Hi, got your point especially with the learning new languages and its importance but you probably mixed things up with the 2 concept you were trying to point out in which I expressed on a different scenario.
What I meant with the "Choose your tools and language wisely" was all about choosing your first list of stack wisely in order to get that first developer job, it would be frustrating if you choose C# for example and found out that there were no demands for opportunities for C# in your area.
And second, for the Ruby on Rails, what I was pointing out was that if I really wanted to learn backend I should have chosen PHP or Laravel since it was the language our backend devs were using at that time, instead of choosing the Ruby on Rails so I could have expand my learning and help backend devs with the projects so I can understand further instead of RoR in which I have forgotten eventually, but you are right, it is okay though to just explore new languages whichever you prefer to, I was just contemplating that I could have done better with the choices I made, just like what you did from PHP to C# they are somewhat related in a sense that you can work on both instead of you knowing PHP and jumping to React/Angular for example, it doesn't make really sense right? but then again, in the end it will always be our personal preference.
And thank you very much for your feedback :)