I'm so glad someone is speaking with common sense. I don't doubt the integrity of well established companies like Symantec, Trend Micro and Macafee.
However, I do think that smaller companies that offer cheaper prices for antivirus and antispyware are suspicious. There are numerous warnings out on the web against this product or that product that offer virus and spyware protection. They offer a free scan, which undoubtedly comes up with "really bad stuff", then they tell you their software can remove it and protect you against other infections for anywhere from $5-20. Sure, that's not much, but if enough stupid people fall for it because they see it as a cheaper alternative, then these companies have made a tidy sum of money at the end of the day.
Do they actually invent viruses and spyware, or do they merely give false reports of viruses and spyware? Regardless, there is deception perpetrated on non-savvy computer users. While I think the conspiracy theorists should be more responsible with their accusations, their vigilance should be mimicked by more computers users.
As for the Windows vs Linux vs Mac debate as to which OS is more vulnerable to attacks, again I applaud your common sense. But I would add that it isn't just an issue of who the biggest company is, it's a matter of this crybaby syndrome that plagues the entire world right now. If a company is vastly more successful than other companies, all the whiners come out of the woodwork and start calling it unfair. Every effort is made, ethical or not, to bring that company down.
In Microsoft's case, false accusations get made by people who are just pissed because it's bigger than all the others. Then, enter the virus writers, who feed off the negative attitudes toward Microsoft target Windows more than anything else. Windows is more vulnerable because it's more widely used and because it is more hated. By the way, did it ever occur to anyone that the virus writers are using Linux to write the viruses that hit Windows and therefore don't want to piss in their own watering hole? Also, keep in mind that as Linux and Linux-based applications (like Firefox, which I use) become more widely used, they are being attacked more.
Make no mistake, I'm no great lover of Microsoft, but they did more to usher in the computer age than any other company. Mac was too stingy and proprietary with its software, and all the Linux varieties required too much technical knowledge to be workable by the average user. So to all those people who hate Microsoft just because it's bigger and more successful, come up with a real complaint and quit piggy-backing other issues (like virus vulnerability) onto your hatred in an attempt to legitimize it.