If programmers deserve to be rewarded for creating innovative programs, by the same token they deserve to be punished if they restrict the use of these programs.

Proprietary software keeps users divided and helpless. Divided because each user is forbidden to redistribute it to others, and helpless because the users can't change it since they don't have the source code. They can't study what it really does. So the proprietary program is a system of unjust power.

EMACS could not have been reached by a process of careful design, because such processes arrive only at goals which are visible at the outset, and whose desirability is established on the bottom line at the outset. Neither I nor anyone else visualized an extensible editor until I had made one, nor appreciated its value until he had experienced it. EMACS exists because I felt free to make individually useful small improvements on a path whose end was not in sight.

One reason you should not use web applications to do your computing is that you lose control. It's just as bad as using a proprietary program. Do your own computing on your own computer with your copy of a freedom-respecting program. If you use a proprietary program or somebody else's web server, you're defenceless.

Proprietary software is an injustice.

Proprietary software tends to have malicious features. The point is with a proprietary program, when the users don't have the source code, we can never tell. So you must consider every proprietary program as potential malware.