It's not that he doesn't hear what Senku is saying. Senku says he doesn't think Inigo is a freak, but Inigo isn't so sure about that. He's had so much experience with people turning down his affection that he's pretty sure he's the abnormal one here. Or much more people would be okay with him.

He sucks in a deep breath though, trying to not get swallowed by the abyss of insecurities that feels more and more like it'll swallow him right up by the day.

".. I think you should observe a little more. There's plenty of people like that, you know?" His voice is a little soft. Like he doesn't want to be patronizing, but does want to give his opinion on the matter here. "Many of my friends back home threatened to literally murder me for touching them. I guess I can't say what it's like where you come from, but you aren't odd at all compared to that."