Not necessarily an MMT specific thing, but yes, the bourgeois focus on taxing labour (wage income) rather than property (capital or land). Interestingly enough, Adam Smith, one of the first liberal intellectuals, argued that land should be taxed rather than labour. The tax topic you illustrate is just one of many examples of how the class and socio-economic basis of things are completely obfuscated by liberal politicians and intellectuals.

To MMT specifically, it only holds as a lacking description of the US dollar. Look at any other currency, ie any currency which is not the hegemonic global reserve currency, and you’ll find that MMT doesn’t hold up.