While I agree mostly with what you said initially. IMO if you think your "smart" or "dumb" based on the results of standardized tests then either way you are just a gullible fool. Standardized tests are designed to sort people based on what they can remember/understand at a given moment in time. A very crappy measure of 'intelligence' (whatever that word really means) indeed.
>> Standardized tests are designed to sort people based on what they can remember/understand at a given moment in time.
Maybe the knowledge-based tests such as the SATs, but there are plenty of aptitude tests that are not based on memorized knowledge.
I also think it is naive to assume that there is some testable form of intelligence completely devoid of cultural knowledge. Someone may be very smart, but if they lack the basic tools to express themselves within a culture then those smarts are behind a real bottleneck.