Perhaps we need to distinguish between syntax errors (related to the rules of grammar) and semantic errors (related to the meanings of words).
Since the comparative and superlative apply only to adjectives and adverbs, it would be a syntax error to try using this construction on a noun: "bricker", "brickest". There are also rules - although they seem a bit vague - about when to add -er or -est (mostly on shorter words) and when to put more or most in front of a word (mostly with longer words).
However, the issue of whether a comparative or superlative is valid at all for a given adjective depends on the meaning of the adjective. And since word meanings are constantly evolving and proliferating, it's probably impossible to lay down any absolute prohibitions. Words can be used in metaphorical or whimsical senses, and exaggerated or paradoxical meanings can be expressed deliberately, for rhetorical effect.
It's probably true that most uses of "more perfect" or "most infinite" would be better expressed in different words, because the writer is using an adjective in a sloppy way, without being fully aware of its meaning. But this might be described as a weakness in writing style, rather than an "error".
A similar issue is the question of which nouns can take a plural. Some dictionaries label certain nouns as "mass nouns" or "uncountable", but it's hard to come up with an example of a noun that can never be used in the plural. Waiters place orders for soups, scientists talk about muds, and political commentators discuss ancient hatreds in - sadly - too many parts of the world.