sinas chinam is hating someone for any reason besides for the following specific case:
that if one sees his friend sinning, he should hate him,
This applies only
1) to one’s companion—one’s equal—in the study of Torah and the observance of the mitzvot.
2) He has also fulfilled with him—with the sinner—the injunction, “You shall repeatedly rebuke your friend.” The word used here for “your friend” (עֲמִיתֶךָ) also indicates, as the Talmud points out, עַם שֶׁאִתְּךָ—“he who is on a par with you in the Torah and the mitzvot,” who, nevertheless, has not repented of his sin, as it is written in Sefer Charedim.
BUT as to one who is not his companion—his equal—in the Torah and the mitzvot so that (as our Sages say concerning the ignorant in general) even his deliberate transgressions are regarded as inadvertent acts, since he is unaware of the gravity of sin, nor is he on intimate terms with him,—not only is one not enjoined to hate him, on the contrary Of this situation, Hillel said, “Be one of the disciples of Aharon, loving peace and pursuing peace, loving creatures and drawing them near to the Torah.”
This usage of the term “creatures” in reference to human beings means that even those who are far from G‑d’s Torah and His service, for which reason they are classified simply as “creatures”—indicating that the fact that they are G‑d’s creations is their sole virtue—even those, one must attract with strong cords of love.
FURTHERMORE , even those whom one is enjoined to hate—for they are close to him, and he has rebuked them, but they still have not repented of their sins—one is obliged to love them too.
(tanya perek 32)