אָמַר רַב: כָּל הַנּוֹתֵן שָׁלוֹם לַחֲבֵירוֹ קוֹדֶם שֶׁיִּתְפַּלֵּל כְּאִילּוּ עֲשָׂאוֹ בָּמָה. שֶׁנֶּאֱמַר: ״חִדְלוּ לָכֶם מִן הָאָדָם אֲשֶׁר נְשָׁמָה בְּאַפּוֹ כִּי בַמֶּה נֶחְשָׁב הוּא״. אַל תִּקְרֵי, ״בַּמֶּה״ אֶלָּא ״בָּמָה״.
Rav said, "Whoever greets his friend before praying, it's as if he made him a private altar, as it says, 'Cease from you man, in whose nostrils there is breath, for how little [בַמֶּה] is he considered' – don't read it as 'for how little [בַמֶּה],' but rather, 'a private altar [בָּמָה].'"
What is this comparison, exactly? The case of a private altar is one who offers a karban to Hashem outside the Beis HaMikdash – but it's still being offered to Hashem. Here, he's neglecting Hashem and instead giving importance to someone else; should the comparison not be to idolatry, rather than to a private altar?