There are millions of millionaires in the US. A lot of fairly normal doctors, lawyers, and engineers will reach this bar by late middle age if they're saving and investing part of their income.

Very cursory search suggests 8% of US adults are millionaires according to CNBC. That means there's something like 300 million non-millionaires compared to 30 million millionaires.

The rate of "billionaire hate" would need to be astronomically higher among millionaires than non-millionaires for millionaires to make up any sort of the majority of people complaining about income inequality.

On top of that, NPR polling suggest about 45% of top 1% income earners on up to about 65% of low income earners (>$35k household) are concerned about income inequality, which flies in the face of the idea that it's mostly jealous millionaires complaining up. A majority of every income segment in America other than the top 1% believes this is a problem.

I didn't mean to suggest that millionares are a majority in the US. But they may well be a majority of those with the time, energy, money, and influence to meaningfully invest into political activities. A majority of those elected to Congress, including major wealth tax pushers Elizabeth Warren and Bernie Sanders, are millionares.

Broke people everywhere may harbor resentment toward the ultrarich, but it wouldn't be the national dialog we're having if millionaires in Congress and their millionaire friends in media didn't find it politically advantageous to turn billionaires into boogeymen.

Broke people everywhere have no use for the distinction between millionaire and billionaire. They are one and the same for those of us that cannot pay their credit card debt. As you say, its patently obvious that the people actually doing the most strident complaining are the members of the virtue signaling, chattering, millionaire class. Since they are complaining on behalf of the poor masses they get to act out their resentment while displaying their virtue. Win, win.