You are right that the tone was a little insulting.
That said, who is the “us” that you are referring to?
A lot of Open Source software is written by people that would not see the use of non-free components for testing as a problem. A lot of Open Source software is written by people that believe in the superiority of collaborative software development but do not have strong opinions on user freedom. The may ever value developer freedom in ways that is incompatible with the most extreme or idealist views of user freedom.
Are you demanding recognition to “us” for all that software?
The post you are replying to was unnecessarily combative. Your is no better and is supported by no better moral high-ground.
The political downvoting in this thread is a turn off for me. However, I completely agree with your statement / question.