I completely agree, but the circumstances which contributed to his decision had a lot to do with his recent close association with her. Gawyn is proud and stupid, but without his warder bond and the Bloodknife doohickeys he might have had the sense to appreciate the vast difference in their abilities, and merely shook his fist impotently from the Andoran section of the battlefield. He'd have been commanding troops under adult supervision, with the usual WoT issues of commanders not being allowed to risk themselves.

I would go so far as to call Egwene's inadvertent contribution to the circumstances of Gawyn's death a net gain for the good guys, because his situation at Tarmon Gaidon removed him from the chain of command and expedited Mat taking over for the corrupted Great Captains. Elayne might not have been so willing to go to him, if she had her favorite brother & First Prince of the Sword to take over for Bashere.

And Lan got that preparation, because it was taken off of Galad's body. Galad was prepared as well. Demandred simply beat him.
And IMO, the Wise Ones' explanation of the phenomenon implies at least that Egwene subconsciously gave tacit consent. There is absolutely no question that Gawyn had no agency in what happened to her, and without the will to act, there cannot be wrongdoing. Also her body and person were not touched, so there is no proof that it actually happened, and was not a creation of her own dreaming mind.

Arguably, if anyone committed rape in that event, it would be Egwene. Desire is not consent (on Gawyn's part), and Egwene is the only one who had a choice of about being there. If she had not been engaging in expressly forbidden activity, she would not have been in a position to violate Gawyn's sexual privacy. If Tylin raped Mat, Egwene raped Gawyn.