High-Period Microsoft looked like it was on track to utterly own the desktop and, therefore, consumer and small business computing world to the point it would be able to keep any non-Microsoft-approved software from existing. (Hardware and software, with Winmodems pointing the way to hardware that only works with Microsoft drivers, not to mention BIOS makers basically giving up and turning their code into first-stage bootloaders for MS Windows.) It killed Netscape and turned IE6 into a millstone around the Web's neck, showing what Microsoft could do to anything it didn't deem sufficiently profitable at the moment. Later, in the early 2000s, Palladium (Trusted Computing Platform) was seen by the most pessimistic as the end of the line for non-Microsoft OSes on commodity hardware: The hardware would only boot encrypted OSes, MS would hold the keys, the government would prosecute anyone cracking the code as a terrorist. Good game, scrub.

The Halloween Documents were only the start of Microsoft's attacks on Open Source in general and Linux in specific; it arguably funded SCO during that company's lawsuit against Linux, IBM's support for Linux, and basic common sense, by buying Linux and Unix licenses from SCO and introducing SCO to BayStar Capital. That isn't so much at arm's length as at finger's length. Around the same time, Ballmer said the Linux kernel was Communism, said it infringed Microsoft's intellectual property, and a bit later called Linux cancer. He also used the "viral license" insult, proving that big companies are sufficiently stymied by the GPL to dislike it. You kinda lose plausible deniability when you call something cancer and then give money to the company trying to sue it out of existence.

But that's Ballmer. Gates all by himself was seen, at least by people who didn't just view him as a Funny Rich Nerd, as a sharp operator at the very least who did nasty things to competitors and had no scruples about doing questionably legal things to win. Jobs without the Cult Of Mac, in other words.