If your question is "was the Terror awful?", I'm sure you'll have a near totality of french people agreeing with you. If you ask "in retrospect, was the Terror awful enough so that the French nation would have been better off without its Revolution?", then I don't think you'll get many agreement.
The deaths associated with the Terror were plentiful, that's true, but this period was also carefully framed by the bourgeois class who took power afterwards. In terms of deaths, it's around 40k people. The american civil war was 700k deaths. Before Trumpism, would any american say out loud that abolishing slavery wasn't worth it?
The thing is people don't care about how many rich people there are out there, as long as they can get a good life out of their labor (good job, good house, etc) but since capitalism has optimized these out of the reach for most people nowadays, then they start to blame rich people for everything, with the definition of the word 'rich' here being very fluid, ending up to mean just about everyone who has more than they do, and not just your Bezos, Musk and Saudi kings, so any taxes on the "rich" ends up only on the hard working middle class again.
Fundamentally the French economy isn't producing enough to support the current level of pension spending, due to a continuously falling ratio of workers to retirees.
Of course an influx of immigrants will cause other issues. But if wealthy people need more population to keep their wealth up, I don't think they care.
It's part of the official discourse.
France overspent in the 2000s and 2010s due to populist politics, and now the chickens have come to roost. Something needs to give in France, otherwise it'll become an Italy 2.0.
I mean, try it with yourself. Imagine that you take your current salary, keep it for 10 years, and have 100% of your spending covered? How life changing would that be to you? Probably a lot.
Understand that the non-wealthy wouldn't get anything new, it would just be a continuance of their current services and benefits. They've have 10 years to increase their GDP by 50% to get the tax revenue to get to a balanced budget. That's simply not happening without obscene inflation, with the corresponding increase in government spending on goods and services, keeping them out of whack.