Because polls aren't accurate enough for decimals to be meaningful.
Generally, this is true. However, it isn't necessarily true. Polls with large enough sample sizes could have meaningful decimals.
Uhh decimals aren't really reliable unless the margin of error were to be <0.5%
So you would need to poll about 50,000 people for a Presidential election, 40,000 for a state election, and 35,000 for a house race
The most people I've ever seen in a poll was about 20,000, and the funny part is it was one of the most inaccurate polls in 2016.
