To make this case let me define some terms.
On the political compass, the Left and Right are on an economic scale, largely delineating between the hierarchy and competition-oriented right, and the equality and sharing-oriented left.
The y-axis operates vertically, where up is authoritarian, meaning more government intervention, while down means libertarian, or less government intervention.
The nature of all life that has ever existed on planet earth trends towards competition and hierarchy, therefore so does human nature. Pesky evolution. Our favorite lobster-man talks about hierarchy extensively, and how it's built into our most primal brain functions. Our societies show this incredibly clearly. And you intuitively know this too, as you want to keep most of your own stuff, want to "get ahead", and outperform your peers, or at least, your past self. Even the past self idea is a conundrum, as being equal to everyone else, any sort of meaningful progress will be scarce, as such progress must be distributed equally. Such wide distribution will make any potential improvement nigh imperceptible and that's even presupposing progress is possible in an equalized society.
The left of the compass is diametrically opposed to these fundamentals of human nature best I can figure. This opposition is disastrous, but that's another topic, lib-left being incoherent as an ideology is an issue.
Being of the left definitionally means you are trying to change ancient human nature (for the reasons we've discussed,) but to be libertarian means you are not willing to use any type of top-down force to facilitate any actions.(Unless it's for purposes of protecting the freedoms and rights of others. I.e. slavery, child labor, etc.) To remain true to both of these values is obviously not possible. There is no way to achieve any sort of meaningful equality of opportunity or outcome in any state-sized population without the use of centralized force for non explicitly freedom protection purposes. And even doing so via use of force has consistently failed
I, therefore, move for lib-left to be pushed out of the compass altogether, and into the sea of political potential to be dissolved; or to be absorbed by lib-right via a natural and inevitable hostile takeover.