No, I agree with you there, and I do think SP is an excellent approach to teaching reading (I don't think it is the only one, and I think ability to read in and of itself will not change the outcome for the 20% or so of children who disengage from school and the written word by about the age of 11). The very basic reading material, in the SP schemes, do require careful sound by sound exercises and using any other method to tackle them would be crazy.
However, I also feel that the very regimented, step by step advance through graded reading material is not necessary for anyone except those who can genuinely not learn any other way, and ignoring the feedback or loop effect of learning by exposure to complex texts should not be eschewed in favour of the plodding, careful SP approach for all.
I think holding back children who are eager, no matter how many mistakes they make, can backfire and kill their enthusiasm. That is why the explicit teaching of sight words (which constitute a very high percentage of the words on any given page a child will encounter) is a good thing (as the National Reading Panel in the US found), as it can help a child to get better at reading through reading, by allowing access to more and more complex texts in a low risk environment (not one where testing is the order of the day), and not risking boring them silly or putting them off by endless tales of cats, mats, pats, rats, etc. The sight words as taught in US schools are not random. Those used most frequently are taught first, with less frequent words learned later. Allowing them access to complex texts does not necessarily guarantee misapprehension -- it provides practice in inferring meaning from context as well as decoding, which is a skill related to the innate ability to infer meaning in spoken language.
Again, the size of a child's vocabulary, and his or her intuitive grasp of meaning, without which children would not be able to learn and use an oral language, have prepared children in vastly different ways to see or hear patterns and rhyme, and to learn to read using any method, including SP. Those with the larger vocabularies who have spent their formative years in a word-rich environment have a huge advantage over those who do not. The following stages of learning to read, to read with comprehension, etc., stem from the quality of the word environment children have under their belts even before they enter school. The process by which recognition of patterns occurs is infinitely speeded up when a child has a large word bank to compare new words with.