I understand the mentality of the chumra-serving flavor of Judaism. Do they think that the chumras are found in any real sources of Judaism? No. Do they really believe there is a foundational truth by which their actions have metaphysical meaning? Nah.
They follow the idea that God rewards the effort itself and the good intent. They know they go way beyond strict Halachah, but in being so strict they must present more effort for which God will doubtlessly be happier about and will bless them and give them a great portion in Olam Habah.
Does it matter that these chumras hide the simple majesty of a number of valuable mitzvot? Does it matter that they waste time on these chumras that they could use doing more productive projects? Of course not. As long as they keep plodding away at what they believe God would want, how can they lose out in the long term (i.e. the afterlife)?
Real understanding of the Torah, or even the world in general is of tertiary importance. Bugs in the water - that is what ensures them eternal life.