#*edit punctuation

Indeed there are some things here: a familiar katana, a kitsune mask and...

Sparkling... Justice...

‘But Ouma considered to stop lying for Shuichi. He truly wanted Shuichi to understand him, and since these are his inner thoughts, he’s not lying.’

As seen, Ouma was loathe to even think of it. He decides - for the entire rest of the event - that it’s not a good idea, and that Shuichi should be the one to change his mindset. When prompted like so, he would [rebuff the idea harshly] as Shuichi’s arrogance- that of thinking people should change for his own convenience. 

This would suggest Ouma’s goal with lying is something he cannot be forward about, and if Shuichi truly wants to understand his reason, then that is on him. He is the one going to Ouma to try and understand him, after all.

On top of that, ‘mind reading’ is only a mechanic in the game; where it comes to Shuichi, this is something exclusive to the Harmonious Heart event, and is limited to one dialogue only. If Shuichi is unable to even understand Ouma’s motivations, then he wasn’t getting anywhere close to the core of the matter in the first place, much less truly reading his innermost thoughts.

Let’s see:

Prophetic Kindness

Hypnotic Despair