IMO immoral is just another word for justifying the means of censor. Big thing about it is that it is subjective in most things. The way you recited your friend sounded to me like she either saw something first that she didnt like and immediately became biased or as a person is generally not comfortable seeing something she knows get interpreted with things that are usually taboo in open society. But fact is that these things are there, so not taking into account the ways of thinking of others before forming a statement or an opinion is tbh pretty close minded. If you ask me, doing things in ways that are more in a serious tone, even if not welcome, are necessary to understand the nature of alot of things, especially how we think and form our thoughts. But i might have interpreted your friend wrong so please do take this with a small biased prejudice towards these kinds of topics.
As to whether I think Reborn is immoral or not, simply no. I personally think Reborn showed some sort of potential the franchise of PokΓ©mon had that the original did not want to go for, for various reasons, but that's another topic.
All in all, Reborn is IMO not the definition of being immoral at all.