It's good to read about these topics, as this gives more understanding.

Of course, people simplify things. So to rephrase, you can as well argue that 'Physics is not about quarks.'

The Nicene Creed mentions heaven and hell, and the Lord's Prayer refers to heaven. So maybe the right way to say it is that Christianity is not only about heaven.

As for the physicality of Creation, the Bible is not supposed to be a Physics textbook. In this sense, the Bible covers both physical and spiritual realms, and it is a common understanding that the Bible has many semantic layers.

It is also quite an oversimplification to take a set of verses out of context to prove something. The Bible is an intricate holistic system.

That said, Christianity is probably the only religion that crosses both spiritual and 'physical' realms. So it's not only about 'up and down', but also about 'left and right'. Unlike the author, I do not see any real bias in the teachings themselves. We still do not know enough about how this world works and what it is that we call real.