Probably because Cradily hissed at him first. I understand that's how she is, but Leon doesn't, and likely also wouldn't understand why she would react that way if he didn't actually make a physically threatening gesture towards you.

[ Being rude verbally? Well, yes, that's just how he is. ]

So, you have an unknown creature hissing at you and then someone saying something like that-- I know you didn't mean it as a threat, but anyone who doesn't know you or Cradily wouldn't know how to take it in a friendly way. It would sound more like a display of power.

[ And a sigh. ]

People come from different circumstances, and I'm sorry that the both of you got off on the wrong foot, but I thought I should tell you how it could have been seen to him.

[ And, honestly, anyone else who had never really dealt with Cradily before and didn't have the best socialization skills. ]