Why do you think that Tom's death was said to be typical?

The comment that Tom's death was "typical" was a racist comment, which generalized the behavior of black men.

To Maycomb, Tom’s death was typical. Typical of a nigger to cut and run. Typical of a nigger’s mentality to have no plan, no thought for the future, just run blind first chance he saw. Funny thing, Atticus Finch might’ve got him off scot free, but wait—? Hell no. You know how they are. Easy come, easy go. Just shows you, that Robinson boy was legally married, they say he kept himself clean, went to church and all that, but when it comes down to the line the veneer’s mighty thin. Nigger always comes out in ‘em.