I'll play devil's advocate here...
Craig Biggio was never a great player. He hit over .300 only four times in a twenty year career, topped 200 hits only once, and had a career line of .281/.363/.433. Moreover, his career playoff line is .234/.297/.323. His only real accomplishment is the career HBP record - which, needless to say, indicates tenacity, not talent.
Those Hall of Fame second basemen that Biggio compares favorably to were not first-ballot players - in fact, most of them waited for years to get into the Hall. Moreover, Biggio does not have the same resume as many of those players in pure name recognition (Nellie Fox and Johnny Evers, for example).
Overall, Biggio was good for a very long time... if you discount his last four or five seasons. I, for one, would prefer to see the Hall of Fame be a veritable 'A-list' of ballplayers... while this would involve removing a great deal of already enshrined players I cannot in good conscience say that another 'good' player deserves to gain entry simply because others already have.