Rather

What does 'they'd rather not' mean here?

The United States has legally converted several times to the metric system - but the conversion has never "stuck" and been favored and adopted widely. One reason is that the SI was not taught as a "new language" - but as something to be converted. We (I was a child in the 1960s and 1970s, learning loads of Metric Conversions) did thousands of unit conversions.
Unit conversions are a lot of arithmetic. Not particularly useful, and lots of work. Uninviting. THIS is most US citizen's perspective of "The Metric System" - unit conversion arithmetic. They'd rather not.