This attitude of "peace at all costs" with heretics and schismatics, regardless of the points of doctrine which separate us, was condemned by Pope Pius XII in 1950 under the name of eirenism.
These advocate an "eirenism" according to which, by setting aside the questions which divide men, they aim not only at joining forces to repel the attacks of atheism, but also at reconciling things opposed to one another in the field of dogma (Humani Generis, no. 11).
11. Another danger is perceived which is all the more serious because it is more concealed beneath the mask of virtue. There are many who, deploring disagreement among men and intellectual confusion, through an imprudent zeal for souls, are urged by a great and ardent desire to do away with the barrier that divides good and honest men; these advocate an "eirenism" according to which, by setting aside the questions which divide men, they aim not only at joining forces to repel the attacks of atheism, but also at reconciling things opposed to one another in the field of dogma. And as in former times some questioned whether the traditional apologetics of the Church did not constitute an obstacle rather than a help to the winning of souls for Christ, so today some are presumptive enough to question seriously whether theology and theological methods, such as with the approval of ecclesiastical authority are found in our schools, should not only be perfected, but also completely reformed, in order to promote the more efficacious propagation of the kingdom of Christ everywhere throughout the world among men of every culture and religious opinion.