Was it just by chance that the building that small plane crashed into housed the IRS?

In Austin, Texas.

Here's the pilot's suicide note (supposedly):

We are all taught as children that without laws there would be no society, only anarchy. Sadly, starting at early ages we in this country have been brainwashed to believe that, in return for our dedication and service, our government stands for justice for all. We are further brainwashed to believe that there is freedom in this place, and that we should be ready to lay our lives down for the noble principals [sic] represented by its founding fathers. Remember? One of these was “no taxation without representation”. I have spent the total years of my adulthood unlearning that crap from only a few years of my childhood. These days anyone who really stands up for that principal [sic] is promptly labeled a “crackpot”, traitor and worse.

Read on. It's long. And it's about taxes. It ends like this:

I saw it written once that the definition of insanity is repeating the same process over and over and expecting the outcome to suddenly be different. I am finally ready to stop this insanity. Well, Mr. Big Brother IRS man, let’s try something different; take my pound of flesh and sleep well.

The communist creed: From each according to his ability, to each according to his need.

The capitalist creed: From each according to his gullibility, to each according to his greed.