The reason why Prince is called a tharki is because he openly made commitments to two different girls within a span of few days and has contradicted himself about them too.
Even Rishabh has kissed girls on their cheeks I agree...but not like Prince's express train of kisses that he unleashes with a crazy speed. I used to cringe hearing those kissing sounds of his.Rishabh flirted with Rochelle in front of Keith who took no offense at all...that shows how it was all in light fun. Warna Rochelle being Rochelle would have objected to it.Rishabh hasnt made 'love' commitments to anyone in the show.
Rish can be called flirtatious or I'd prefer the word romantic but not Tharki from any angle. There is a visible difference between the way Rish hug, kiss or flirt with a girl as compare to Prince.