trisquel 6.0 GNU/linux has proposed to install the nonfree codec

Hello, Trisquel

I like the GNU/linux and ideas of free software.
Three days ago I decided to move from ubuntu
to the trisquel 6.0 GNU/linux, because it's like
comfortable ubuntu, but it uses only free software.

I open www.mutopoia.org and passed on the link to the site
http://www.mutopiaproject.org/ftp/ClarkFS/Marche_aux_Flambeaux/Marche_aux_Flambeaux.mid
OS showed me this dialog(1.png)
I live in Russia and use russian language, so I'll translate this
for you.

"Can I find the codec?
Some necessary software for opening the file are not installed.
Codecs for playing are needed.
Can I find necessary codecs to open this file.

Maybe some codecs are not officially supported.

cancel find"

I pressed the button "find".
The new dialog appeared(2.png).

"Can I install nonfree programe?"

Next eleven lines of the text in dialog is about some restrictions in different countries.
OS proposed me to install a nonfree superstructure for Gstreamer.

This dialog puts users between the difficult choice - Use only free programes or Install this codecs?

I hope that you know about this problem.

Best wishes

Voloshin Kirill