Actually, the therapeutic thing for him to say to you in this situation would be "Thank you for sharing that. I hear you. I'm glad to know that you consider this a safe place for you to express and explore your feelings. I want you to know there's an open invitation to talk more about those feelings here in therapy... if you should choose to."

This therapist is negligent and ineffective at best and he's outright damaging at worst. Your feelings of platonic love for your therapist are healthy, natural, expected, and absolutely okay. The fact that he doesn't understand this and has shamed and silenced you regarding your own feelings is appalling to me.

Edited to add: I tell my therapist that I love him on a weekly basis. He doesn't say "I love you too" but he responds with warmth and empathy every single time. And every time he reminds me that those feelings are welcome here and we can explore them in therapy as much as we need to. If he feels uncomfortable about hearing the words "I love you" from a client he certainly keeps that all to himself and works on his own stuff on his own time so it doesn't impact my therapy.