The use of platform specific code was a performance necessity at the time, everyone did it. Part of the promise of Windows 95 was that it could run your Windows 3.1 programs. They bent over backwards for a ton of programs, but not WordPerfect. Microsoft also had an early access program to Windows 95. WordPerfect applied for it - and was denied access. After that the OS/2 bet was their only real hope.

The truth is that Microsoft had a long and documented history of using one monopoly to leverage into another. Over and over again they lost antitrust lawsuits, but internally regarded them as speeding tickets on the way to greater monopoly power. This history showed up in court. The internal documentation on the WordPerfect case showed up in the Netscape case, and is part of why Mocrosoft won.

It wasn't until the EU started charging Microsoft over $400 million per day for noncompliance in 2006 that Microsoft's attitude started to change. Now I see them as just normal big guys with a worse than average history. But back in the 90s and early 2000s? They EARNED the title of "evil empire".