Sorry if i didn't explain it well enough. I agree with you, the black hole and tesseract stuff did happen but the audience is meant to look at the emotional significance of the events as opposed to taking it at face value. I don't think saying that the ending was a dream really helps or affects what the movie tries to convey.
I fully agree with what you said. I think what your saying is shown well in the speech Brand makes about love telling her what to do. In her desperation and fear after having calculated the time dilation numbers wrong (should have been less than 23 years) she considers the possibility of love of being something more that can be explained by science (the same sentiment is made by Cooper in the black hole) as it is the only gut feeling inside of her that pushes her after her science had failed her.
I think the reason why some people didn't get it is because we are so used to the "fact" that love simply cannot be explained by science and when that shows up in a film it immediately seems pretentious. Nolan is a smart filmmaker and for someone who is often described as being cold and clinical, I don't think he would have used the idea unless he was trying to consider something that most people would shun away from.
We really need to consider the idea of our emotions being explained by science.
I think that the ending is real in the sense of the movie and the audience is meant to look at the significance of the events. After Cooper enters the black hole, we aren't meant to take it too literally in the sense that this actually happens and there is no meaning nor is it strictly meant to be a dream, but his whole ordeal ties in with the theme of a father seeing his daughter grow up (i.e. the contrast of seeing her as a child in the black hole and as an old woman on her death bed). Then the last bit of him going off with TARS echoes the idea from 2001 of humanity taking the next step (i.e. from the monolith on earth to the one on the Moon).
Additionally, Nolan only uses the science to convey a sense of reality of interstellar travel so that we may become more involved in the story. The film isn't meant to be 100% accurate in terms of science. The last bit highlights the power of film in that it uses the reality of space travel shown in the film to evoke certain emotions in the audience even though the events don't seem realistic. It allows us to make our own interpretation in the same way as 2001 without explicitly (relatively) saying: "Hey, this is where you interpret." Much like 2001, Interstellar is a film (as a whole) that makes you feel something rather than tell you how to respond.
Like Peter Travers of Rolling Stone said the film "blends the cosmic and the intimate".
This is simply my interpretation and others may see it differently. I just hope this gives you another perspective on the film