Because just like in the stop light case, due to an increase in traffic, which resulted in an increase in accidents, which required a change to the process, the people who are in charge of voter integrity want to do everything they can to reduce/eliminate fraud.
And...just like in the intersection where there's now a stop light that forces you to wait where before you might have just had to stop and look both ways, voting rules might be an inconvenience to some, but they're not designed to discourage one party or one race from voting. To believe that is just ignorant.
But I'll make the point again....if you're too lazy to accept a little inconvenience ONCE EVERY 4 YEARS, then perhaps you're too lazy to understand the issues and what you're voting for.