Because Ephraim hath made many altars to sin, altars shall be unto him to sin. Many altars to sin - Though it does not appear that the Jews in Babylon were obliged to worship the idols of the country, except in the case mentioned by Daniel, yet it was far otherwise with the Israelites in Assyria, and the other countries of their dispersion. Because they had made many altars to sin while they were in their own land, they were obliged to continue in the land of their captivity a similar system of idolatry against their will. Thus they felt and saw the evil of their idolatry, without power to help themselves.
Related Commentaries of Hosea 8:11
Hosea 8:11
11 Because Ephraim hath made many altars to sin, altars shall be unto him to sin.