If you install and use proprietary software, you didn’t anything wrong.
A wrong is being done to you.

People think that we say that it is unethical to use a nonfree program.

Many supporters ask whether it is ethical for them to use certain proprietary software.

Meanwhile, others condemn us for (they believe) attacking them for using the proprietary software they like. Both reactions are based on that misunderstanding.

What we really say is that a non-free software is unethical to the user.

http://gnu.org/philosophy/is-ever-good-use-nonfree-program.html tries to explain this.

People, could the hostile reactions you’ve seen could be based on that misunderstanding?