I don't think that's why kids hate it. Rather, teachers fail to explain the underlying motivations, the reasoning and the purpose which makes math feel like arbitrary decisions.
I'd argue math is much more uncertain than other subjects. What's the purpose of the endoplasmic reticulum in your cells? Just memorize the textbook. Find all X such that [statement] is true? You better have some creativity! Or a lot, depending on the problem.
Some accompanying evidence for uncertainty: https://xkcd.com/2117/
Minor notes after researching the tools some more:
I'm not an artist but nearly all of the aforementioned points lead me to have a resoundingly negative view of the project. Maybe I'm cynical but it seems they intend to make the tool subscription-based in the future after gaining enough market share.