Why does the Navi rebuke Yisrael right after the consolation?
Radak: So Nevi'im speak ? rebuke and consolation. Hashem already told him to take a wife of Zenus; now, He gives another Mashal.
What is "Ahuvas Re'a"?
Rashi: She is dear and beloved to her husband, and she is Mezanah under him, like Hashem's love for Yisrael, and they are Mezaneh under Him to serve idolatry.
Radak: You will love her, and she will be a companion to you. Afterwards, she will be Mezanah with others. The first Mashal was about Yaravam ben Nevat and those who came after him. They were Mezaneh away from Hashem, and abandoned Avodas Beis ha'Mikdash and served calves afterwards. Achav came and increase evil, and made Ba'al and Asherah. This Mashal adds that Hashem initially loved Yisrael like a wife beloved to her husband ? it is a great love. A man does not love every wife equally ? "va'Ye'ehav Yakov Es Rachel" (Bereishis 29:18). David said [that he loved Yonason] more "me'Ahavas Nashim" (Shmuel II, 1:26), i.e. his two wives who were dear to him. Even so, Yisrael turned to other gods!
Malbim: The first Mashal compared Yisrael to a married woman who is Mezanah under her husband. Hashem commanded Hoshe'a to marry such a woman. Now He commanded him to love a Zonah, but not via marriage; she will be single. He loves her greatly, but she is Mezanah for the Esnan that they give to her, also with men other than her beloved. She is not called a Zonah, for she is single 1 , but she betrays her beloved. This is a Mashal for Yisrael after their Galus. Hashem sent them away and nullified the previous Eirusin; she became like single ? He said "Lo Ami Atah". Even though he does not love her openly, he loves her and oversees her covertly, with hidden Hashgachah. Hashem's love for Yisrael in Galus is compared to this. It is not like a husband and his betrothed, rather, like a man for his concubine. So Hoshe'a should take her
Why can't a Zonah be single? Rashi (Yevamos 61b) says that R. Eliezer holds that only Zenus of a married woman makes her a Zonah forbidden to Kohanim, but the Halachah does not follow him! (PF)
What are "Ohavei Ashishei Anavim"?
Rashi citing Menachem: They love cups of wine, i.e. to get drunk. They do not engage in Torah. Also elsewhere they are rebuked "ha'Shosim b'Mizrekei Yayin" (Amos 6:6).
Radak: They love grape wine. They should have loved Toras Hashem and His Mitzvos, and constantly meditated on love of it, for it teaches to them the good, straight path! They cast off themselves the yoke of Torah, and loved worldly pleasures and their desires. "All who stagger in wine will not grow wise" (Mishlei 20:1). "Hoy Mashkimei va'Boker Shechar Yirdofu Me'acharei va'Neshef Yayin Yadlikem" (Yeshayah 5:11).
Malbim (according to the Nimshal): Yisrael turned from their Beloved to serve other gods. They are not at their previous level, of a wife that her husband feeds her. She went to lovers, thinking that they feed her - "Elecha Acharei Me'ahavai Nosenei Lachmi u'Meimai" (2:7). Now, in Galus, she does not receive food regularly, not from her beloved (he is not her husband), and not from lovers, for she has no lovers. She is like a lowly harlot who is Mezanah for a cup of wine that the man gives to her. They are her lovers via a cup of wine! So in Galus, Yisrael turn from Hashem for a small matter ? "Tachas Asher Lo Avadta Es Hashem Elokecha b'Simchah uv'Tuv Levav me'Rov Kol; v'Avadta Es Oyvecha? b'Ra'av uv'Tzama" (Devarim 28:47-48.)