The above cuttings from Harrison's book look to be taken out of their broader contexts, and what they interestingly suggests, as presented here, is that one can fail at meditation, and drastically so. Failure at meditation does, indeed, happen, all too often. What I have seen frequently with such failures are subsequent attacks on meditation, either in a generalized manner or in terms of specific technique, as we have seen graphically illustrated in this thread. However, in going through Harrison book, which is not actually an anti-meditation screed, we do see why some of the failures happen, and we do see what he is offering as correctives.
Interestingly the OP
of this thread is essentially a basis for a criticism of a meditation practice in general, but sadly as the thread unfolds, the criticism is not based upon a careful understanding of what is it criticizing.
Certainly, meditation practice, either in a generalized sense, or specific techniques can be, should be, open to criticism, but ideally these criticism need to be done from a place of actually understanding what is being criticized.
An interesting page from the book retro recommended by steven harrison