Injecting or substituting ads is shady. You're degrading the experience with less targeted and lower quality ads at the expense of Facebook's brand and perceiv

Injecting or substituting ads is shady. You're degrading the experience with less targeted and lower quality ads at the expense of Facebook's brand and perceived quality of service. The end user assumes the crappy experience is from Facebook itself. How's this different from malware that injects/substitutes ads?