self-serving interpretation; arguing to suit oneself; drawing water to one's own field
A yojijukugo idiom. Literally 'drawing water to one's own rice paddy', used for interpreting facts, rules, or arguments in a way that benefits oneself. Often used critically.
His explanation is self-serving; he only says what suits him.
That interpretation is a blatant case of twisting things to one's own advantage.