In the interpretation and application of this act, the public policy of this state is declared as follows:
Negotiation of terms and conditions of labor should result from voluntary agreement between employer and employees. Governmental authority has permitted and encouraged employers to organize in the corporate and other forms of capital control. In dealing with such employers the individual unorganized worker is helpless to exercise actual liberty of contract and to protect his freedom of labor, and thereby to obtain acceptable terms and conditions of employment. Therefore it is necessary that the individual workman have full freedom of association, self-organization, and designation of representatives of his own choosing, to negotiate the terms and conditions of employment, and that he shall be free from the interference, restraint or coercion of employers of labor, or their agents, in the designation of such representatives or in self-organization or in other concerted activities for the purpose of collective bargaining or other mutual aid or protection.