I completely disagree. I learned Java after C++ and I found it to be a breeze to learn - and I was self taught. Python is a good language too, granted.
For the record, I also learned C++ first. I also found Java to be a breeze. And then I discovered a whole world of other languages, and learned that in the grand scheme of things, Java and C++ are actually really similar to each other. Even Python is not so incredibly different, though it is vastly easier thanks to dynamic typing.
Compare any of these to stack based languages (Forth), array-based languages (APL), dataflow/graphical languages (LabView), homoiconic languages (Lisp), dependently-typed languages (Coq), etc. There are so many paradigms that are so dizzyingly different from each other. C++ and Java really are much more similar than they are different.
And it's worth pointing out that many if not most of these, though they would probably induce shock in a typical C++/Java programmer, are actually built on top of a small set of core concepts that is probably more coherent than either of Java or C++. And this matters a lot for people who are learning truly from scratch. There isn't necessarily enough data to make any definitive statements here, but there are schools that start with e.g. Haskell as a first language, and offhand I would probably say they get off the ground faster than a lot of Java/C++ introductory courses I see.