Answer:
I personally wouldn't say please kindly. Not because it sounds rude, to me it just doesn't sound right in the natural flow of language that I am familiar with. I could see how someone might interpret that as being rude, though I would not. Maybe they see it rudely because when you say please kindly, they imagine it as you telling them in which way they should act while they do whatever it is you are requesting. Basically telling them that they must act kindly even if they do not feel that way. Maybe they think you are telling them how to feel, I guess? I do not see it that way, but that's the only train of thought I can seem to think of that would think it is rude, and not just unusual.