No contradiction. Liberals always have been and still are the only ideology that consistently supports liberty. Conservatives consistently oppose liberty. Libertarians consistently oppose government, which they think is consistently supporting liberty but it's not.
What is liberty? Absence of government? No. That's what libertarians say, and what conservatives say when it's convenient to them (e.g., when the government policy or program under scrutiny is one that either helps poor or middle class people or restraints corporate power) and shut up about when it's not (e.g., when the government policy or program under scrutiny is one that directly restricts liberty, such as anti-abortion laws or laws discriminating against minorities). But it's only true some of the time.
Liberty is the ability to live and act without being held down by a boss. Exactly who the boss is doesn't matter. It might be -- in past eras very frequently was -- government; in that case, liberals want government restrained and subjected to rule of law while conservatives don't. (Or didn't. Another part of the dynamic is that what was once a liberal issue can become one everyone believes in over time, after liberals win. Which in the end we always do.)
Sometimes, though, the boss is a private, non-government agency. This can be a literal boss (one's employer), or merely a very powerful corporate entity capable of shutting out small-business competition, polluting the environment, and wrecking people's lives and livelihoods in its quest for profits. In a situation like that, liberals are the ones favoring government, which is the only thing capable of restraining such an entity, while conservatives oppose it.
Shorthand: When government itself is the threat to liberty, liberals oppose government power and conservatives support it.
When something else is the threat to liberty and only government can keep it restrained, liberals support government power and conservatives oppose it.
The CONSISTENT variable here is not support or opposition to government power. It's support or opposition to liberty. Liberals support liberty. Conservatives oppose it.