Historical Calvinist writers affirm the universal aspects of the atonement. There are many, many quotes - including from Calvin - but here are just a few:
Charles Hodge in Systematic Theology (vol. II) p. 546:
"There is a sense, therefore, in which He died for all, and there is a sense in which He died for the elect alone."
AA Hodge in Outlines of Theology, p. 416:
"Nor is there any debate as to the universal reference of some of the benefits purchased by Christ. Calvinists believe that the entire dispensation of forbearance under which the human family rest since the fall, including for the unjust as well as the just temporal mercies and means of grace, is part of the purchase of Christs blood. They admit also that Christ did in a sense die for all men, that he thereby removed all legal obstacles from the salvation of any and every man, and that his satisfaction may be applied to one man as well as to another if God so wills it."
R.B. Kuiper in For Whom Did Christ Die? pp. 78-79:
"According to the Reformed faith the divine design of the atonement is in an important respect limited. But the Reformed faith also insists that in other respects it is universal. It can be shown without the slightest difficulty that certain benefits of the atonement, other than the salvation of individuals, are universal.... Therefore the statement, so often heard from Reformed pulpits, that Christ died only for the elect must be rated a careless one... The particular design of the atonement and its universal design in no way contradict each other. Nor do they merely complement each other. They support and strengthen each other. In final analysis they stand and fall together."
LDG