Can’t speak for anyone else but I may be able to answer this.
A lib is a liberal, someone who is pro-capital, not an anti-capitalist (very little overlap with how liberal tends to be defined in ordinary language in the US). Optics, relating to how people see the event, is idealism not materialism. Liberalism is idealist, unlike Marxism, which is materialist.
The dig at liberalism and aesthetics is likely a critique of the implication that what this looks like has much to do with the material reality. That’s an aesthetic argument. It doesn’t matter what this looks like because the optics don’t affect the material relations. Someone who elevates the optics at the expense of the material relations is making an idealist, likely a liberal argument.
Hence the comment embodying an aesthetic argument of the kind that liberals often make.