I disagree. There are plenty of examples of liberal anti-capitalists such as David Ellerman

The difference between liberal and left is not fully capitalism dependant. It has more to do with lateral vs horizontal power structures. Liberal rhetoric tends to focus very much on personal property rights which means it basically is a machine to enable unchecked capitalism because it resists anything that would enable seizure or social checks on acquisition or regulation. It reinforces heirachy by legitimizing and protecting wealth and ensuring it snowballs creating greater inequity over time. Any check on what is considered personal property is anti-liberal to some extent.

There are actually liberal and social attitudes towards capitalism. Anti-trust measures, stock restrictions, union organization, reabsorbing privately held services and property into public trusts and services. These things exist as social counter measures to unchecked capitalism but not an attempt to explicitly remove the basic idea of investment capital existing in some form or another. The focus on decentralization of wealth agrigation and empowering labor still makes it nominally left of center.