Of course Valve has policies designed to meet the expectations of rights holders, that's a given and I'm unaware of any serious business on the planet selling goods created by other companies that doesn't have such policies and enforce them so they can continue to sell those goods. This is a blanket policy that Valve enforces regardless of the publisher.
Valve has been banning accounts for circumventing region restrictions for as long as the feature has existed, and long before Sony added their games to the platform. Just because these policies were designed to appease rights holders doesn't change the fact that it's at Valve's sole discretion to enforce compliance (at risk of losing publishers).
Let's be real here, there is no risk of losing publishers over not bending the knee to publishers over unreasonable demands (such as banning entire accounts).
Publishers have been trying to stay off Steam for much more strategic reasons, and they have always come crawling back, admitting they fail at distributing games on their own. They would never seriously consider ditching the platform over petty grievances like this.
Valve has been banning accounts for circumventing region restrictions for as long as the feature has existed, and long before Sony added their games to the platform. Just because these policies were designed to appease rights holders doesn't change the fact that it's at Valve's sole discretion to enforce compliance (at risk of losing publishers).