In this case self-preservation is good business sense. It has been pointed out numerous times in numerous threads that this is a business decision for both Byrd and the Bills. Byrd knows that risking his future by playing this season on the tag is not good for his future (self-preservation if you will) or a sound business decision.
Some, including me, find Byrds actions to be less than admirable or even worse, but I find no flaw in his logic. The Bills, also in my opinion, pulled a less than admirable move by tagging Byrd in the first place.