Yup, just like it's employment 101 to not discuss salaries.
Lack of communication and organization is a fantastic way to keep workers in line. Genuinely all it takes are a handful of socialists in an environment of heavily exploited workers to get a union going. They can all feel the material harm capitalism is causing, but lack the language and means to express and resist that harm.
When socialists provide it (via politics in the workplace), that harms companies. When communication takes place (salary sharing, organization tactics, etc.) you place a strain on the bourgeoise to behave more inline with worker expectations. This isn't what capitalists want.