The Torah says:
לֹא־תַטֶּ֣ה מִשְׁפָּ֔ט לֹ֥א תַכִּ֖יר פָּנִ֑ים וְלֹא־תִקַּ֣ח שֹׁ֔חַד כִּ֣י הַשֹּׁ֗חַד יְעַוֵּר֙ עֵינֵ֣י חֲכָמִ֔ים וִֽיסַלֵּ֖ף דִּבְרֵ֥י צַדִּיקִֽם׃
You shall not judge unfairly: you shall show no partiality; you shall not take bribes, for bribes blind the eyes of the discerning and upset the plea of the just. (Devarim 16:19)
Rashi comments on this verse:
כי השחד יעור. מִשֶּׁקִּבֵּל שֹׁחַד מִמֶּנּוּ אִי אֶפְשָׁר שֶׁלֹּא יַטֶּה אֶת לִבּוֹ אֶצְלוֹ לַהֲפֹךְ בִּזְכוּתוֹ:
כי השחד יעור FOR BRIBERY DOES BLIND — As soon as he (the judge) has accepted a bribe from him (from one of the parties) it is impossible for him not to incline his heart to him trying to find something in his favor.
This would probably be enough to ask my question, but the gemara (Ketubot 105a-b) has a whole discussion about how accepting bribes will lead to unjust rulings. This all seems rather obvious. It seems to me like we don't need the Torah or Rashi or the gemara to explain to us why bribery is bad and will lead to improper judgements. It should have been sufficient for the Torah to say ״לא תקח שחד״ and leave it at that. So why does the Torah and subsequent commentaries elaborate to such an extent?