I reject the notion that aesthetics is arbitrary. It is not. I also reject the mystification and the dismissive progressive fallacy that the only reason anyone might oppose change is because they're crusty old reactionary humbugs (of course, if aesthetics is arbitrary, "progress" has no meaning). Le Corbusier's Paris is objectively hideous. It is objectively a nightmare. It would objectively be immoral to inflict something like that on Parisians. It would objectively harm the common good. A nihilistic misanthrope consumed with hatred for humanity, and himself, could do no better. For this reason, I detest language like "clinging to an aesthetic past". It is a hollow comment that begins from faulty assumptions about aesthetics.

Of course, we often make aesthetic judgements in a relative fashion. People visiting Paris today might say Paris is beautiful, but what they mean is more beautiful than some other point of reference. Spend enough time in a beautiful city and your standards will shift such that you will be disappointed by aesthetically inferior cities you had previously thought were beautiful when you revisit them. This is good. Let our tastes become more refined so that we may make the world a more beautiful place. Let us resist mediocrity and ugliness.

So perhaps those critics of Haussmanian Paris were making such a comparison. I certainly don't think Paris is the most beautiful city, but if you had grown up in a Corbusian nightmare or some aesthetically lesser locale, then it would certainly be an upgrade and perceived as such. Still, Haussmanian Paris is at least built according to classical principles and that is the most important factor.

Of course, I am not opposed to development in the realm of art and architecture and so on, but modernist travesties like the ones pictured are not an authentic development, but a barbaric revolt against the past rooted in hubris, madness, or some other defect.