You said: ...it sounded like you were dismissing bad philosophies as not real philosophies
The problem I think begins with academia, which has pulled this trick of calling anything that addresses philosophical problems, philosophy. It is a hangover from theology, which included anything which attempted to address theological issues as theology.
But philosophy is not theology. The material of philosophy is not mystical, not opinion or revelation, not subjective experience. The material philosophy deals with is objective, and every bit as objective as that dealt with by geography, astronomy, physics, chemistry, or mathematics.
Philosophy is the discipline that seeks to understand what the nature of existence is (it has a real objective nature), what the nature of mind is (it has a real objective nature), what the nature of knowledge is (it has a real objective nature), what the nature of values is (they have a real objective nature).
If I took a course in chemistry and what they taught me was, 1. all the things chemistry attempts to discover the nature of and the problems of doing that, 2. all the different crackpot theories anyone has ever had about chemistry, 3. the theories of alchemy, 4 the phlogiston theory of combustion, but never taught me any real chemistry, I would want my money back.
Take a course in philosophy and what is one taught? 1. all the kinds of problems philosophy tries to solve, 2. all the different crackpot philosophies that have been propounded throughout the ages, 3. Platonic realism, idealism, skepticism, 4 logical positivism and linguistic analysis, and this is supposed to be philosophy; but, unless one has been accidentally introduced to the ideas of Aristotle, Peter Abelard, William of Ockham, Sir Francis Bacon, John Locke, or Ayn Rand (very unlikely) along the way, it is almost certain they have learned no philosophy at all.
Yes, I dismiss all the mistaken and incorrect attempts at philosophy as non-philosophy just as I dismiss all the mistaken and incorrect attempts at chemistry as non-chemistry.
You asked a fair question. Here are some mistakes in Objectivism:
1. There is no ontology. (Well, there isn't.)
2. In concept formation, the idea that similarity consists of qualities or characteristic common to two or more existents, with the exact measurement of those qualities left out, is incorrect. The similarity consists of essential qualities or characteristics shared by two or more existents, but with different non-essential qualities left out (but always implied and possible). Measurement is only a quality, and is sometimes the differentiating non-essential quality. But many times it is a different non-essential quality that differentiates between units or particulars of a concept. Some examples of concepts for which the "left out measurement" idea does not work are: logic, verb, preposition, beer, cheese, milk (is 'goats' a different measure than 'cows'?), brother, uncle, history, man-made, concept, memory, cough, blink, malaise, smallpox, cancer, ethics, politics, value, esthetics. Units of concepts for most adjectives are not differentiated by a measurement of some common quality, for example, satirical, mysterious, pregnant, alive, dead, true, false. What is the difference in the measure of fruitiness between a pear and an apple. They are both fruit, but it is non-essential qualities (those that do not make them fruit) that are different, not a difference in the measurement of some common quality.
3. I can only mention what the mistake about perception is, because the explanation is lengthy. Rand, Peikoff, and Kelly all assert the brain integrates sensations into percepts. Here is Peikoff, "The integration of sensations into percepts, as I have indicated, is performed by the brain automatically." [Ojectivism: The Philosophy of Ayn Rand page 54]
There are three mistakes here. First, it requires the brain to have the mystic ability to know ahead-of-time which sensory data to integrate into entities and which to integrate into background. Peikoff does try to get around this problem by suggesting the brain, learns, through experience, how to do this. The solution is problematic, but unnecessary in any case. Second, it supposes the perceived qualities are first "separated" by the nervous system, as though individually sensed, then "reassembled" by the integrating process of the brain. Third, it supposes that what the nervous system does is create sensory data from whatever stimulates it, which data is then processed by the brain to create the percepts, like a computer. But this is exactly the objection Kant made about the validity of perception.
These concepts are wrong, but easily corrected. Perception is a totally valid and accurate apprehension of reality. Unfortunately, objectivism, even Kelly's excellent attempt to, does not explicate how this is so.
I do not oppose Objectivism in any way. It is the best and most complete philosophy to date, sweeping away junk yards of mystic nonsense and integrating into a comprehensive philosophical view the best of historic philosophy and advancing the whole discipline (especially in the areas of epistemology and ethics). Like any other discipline, it is open ended and much more needs to be done, and I sadly see very little new work being done. A lot of objectivists have settled, assuming they have all the answers. They have a lot, but it's just a beginning.