The fantastical justifications of Chazal

 In last weeks parsha וישב the Torah relates a very straightforward story. Yehuda is traveling, sees what he thinks is a prostitute (it's really his daughter in law), negotiates a price with her, gives her security, has sex with her, and then later tries to find her to pay her. Chazal and the מפרשים however, are bothered by a very simple question. How could one of the holy שבטים, the progenitor of the kingly dynasty and moshiach, sleep with a prostitute. Therefore the Gemara (Sota 10a) makes up a whole dialogue that it attributes to Yehuda to justify Yehuda's conduct.

רַבִּי שְׁמוּאֵל בַּר נַחְמָנִי אָמַר שֶׁנָּתְנָה עֵינַיִם לִדְבָרֶיהָ כְּשֶׁתְּבָעָהּ אָמַר לָהּ שֶׁמָּא נׇכְרִית אַתְּ אָמְרָה לֵיהּ גִּיּוֹרֶת אֲנִי שֶׁמָּא אֵשֶׁת אִישׁ אַתְּ אָמְרָה לֵיהּ פְּנוּיָה אֲנִי שֶׁמָּא קִיבֵּל בִּךְ אָבִיךָ קִידּוּשִׁין אָמְרָה לֵיהּ יְתוֹמָה אֲנִי שֶׁמָּא טְמֵאָה אַתְּ אָמְרָה לֵיהּ טְהוֹרָה

Rabbi Shmuel bar Naḥmani says: She provided eyes [einayim] for her statements, i.e., with her words she provided an opening [petaḥ] for Judah to solicit her. When Judah solicited her to engage in sexual intercourse with him, he first attempted to verify her status and said to her: Are you perhaps are a gentile? She said to him: I am a convert. He asked: Perhaps you are a married woman? She said to him: I am an unmarried woman. He asked: Perhaps your father accepted betrothal for you and you are unaware of it? She said to him: I am an orphan. He asked: Maybe you are impure? She said to him: I am pure.

Amazing, Chazal make up a whole dialogue out of nothing where Yehuda asked a prostitute is she an idolater, married, a nidda. Why, because they couldn't accept that Yehuda simply slept with a prostitute.

The מפרשים are still bothered by the question how could Yehuda have sex with a prostitute? I saw 3 answers in the מפרשים:

1. He was מקדש her
2. He was מיחד her so it wasn't זנות
3. He took here as a פילגש

IMHO these sound like desperate rationalizations for Yehudas conduct. To think that Yehuda married (was מיחד, or took as a פילגש) a random prostitute he met on the road is ridiculous and contradicted by the text itself. When Yehuda searches for her to pay her (after he had sex with her) he asks the people where is the prostitute, clearly showing that he still considered her a prostitute. 

IMHO, this greatly impacts Chazal's credibility, we see that they made up all kinds of unbelievable rationalizations to justify sinful conduct by biblical figures. Where is their intellectual honesty? If they could make up stories like these what else did they make up?