The GNU General Public License (GNU GPL) is a strongly copylefted Free Software license which uses the word "prohibit" for multiple things. I'd hardly think an organization would put such language in their license if they objected to the use of the words as you think they do.
For example, Section 2 of the GNU GPL version 3 does what it can to clearly prohibits proprietarization: (emphasis mine)
You may make, run and propagate covered works that you do not convey, without conditions so long as your license otherwise remains in force. You may convey covered works to others for the sole purpose of having them make modifications exclusively for you, or provide you with facilities for running those works, provided that you comply with the terms of this License in conveying all material for which you do not control copyright. Those thus making or running the covered works for you must do so exclusively on your behalf, under your direction and control, on terms that prohibit them from making any copies of your copyrighted material outside their relationship with you.
This prohibition is a good thing because proprietary software subjugates the user to the developer's control; that's why proprietary software is developed and distributed. Proprietary software is often malware and thus a mechanism for spying on the user, removing programs the user wants to keep installed, and more anti-freedom activities that deny users complete control over their computer. This all happens to any user regardless of how skilled they are with computing, or how willing they are to take advantage of their software freedom.
Section 3 of the GNU GPL version 3 prevents conveyers from exercising legal power to forbid circumvention of technical measures:
When you convey a covered work, you waive any legal power to forbid circumvention of technological measures to the extent such circumvention is effected by exercising rights under this License with respect to the covered work, and you disclaim any intention to limit operation or modification of the work as a means of enforcing, against the work's users, your or third parties' legal rights to forbid circumvention of technological measures.
Section 7c of the GNU GPL version 3 "prohibits" misrepresenting material from upstream conveyed copies ("Prohibiting misrepresentation of the origin of that material, or requiring that modified versions of such material be marked in reasonable ways as different from the original version").
Section 11 of the GNU GPL version 3 includes a prohibition to make sure certain patents don't lock users out of exercising the freedoms the license grants.
The details matter: To understand what's going on you have to understand what is being forbidden and prohibited, why these allowances and restrictions are necessary, which users are affected, and how and then evaluate if those causes and remedies are right and proper.