Simple
Apple probably provides programs for 1 of 2 main reasons.
1. Provide a program/driver for another non-Macintosh product (i.e. iTunes for iPhone, iPod, etc).
2. Promote something as a standard (i.e. Firewire, Quicktime, Bonjour, Safari, etc).
Microsoft probably provides programs for 1 or 2 main reason.
1. Make more money
2. Avoid some kind of legal trouble (i.e. prior lawsuits, legitimize another operating system, etc).
Apple bashes Microsoft because it is easy and they want to gain market share. Obvious.
Microsoft hasn't really been bashing Apple, except to say that they cost more in the "Laptop Hunter" ads. In the "I'm a PC" ads, they tried to save self esteem for PC users. In the Seinfeld ads, they were completely nuts.
The only thing Apple's competition has been saying about Apple is that they cost more, and they have been looking for dirt real hard. All those SEC claims, App Store rejection complaints, Google board flap, Jobs health issues, etc, are just cheap shots to slow down a company that is doing things right.
The best they can say, which is true, is that Apple's quality isn't perfect, or that Macintosh isn't invulnerable to malware. They don't pick on those "soft underbellies" because they have a worse track record.