They had a history of outright stealing of other companies' intellectual property. They had the habit of deliberately misleading people about other companies' products. Those of us who lived through the 90s lost all trust in Microsoft. They will never ever regain that trust.

Some places to investigate for your own education: 'The Halloween Documents', 'AARD Code', 'Embrace, Extend, Extinguish', 'STAC software stolen, DriveSpace released','Exclusionary Licensing', 'Sendo', 'XBox 360 Disk Failures Suppressed', 'Microsoft Litigation', etc, etc, etc.

Here. I'll get you started with the 'Halloween Documents' - http://www.catb.org/~esr/halloween/