At least some disclaimers aren't just noise—they add context that would otherwise be missing to help the reader navigate the subtext. The "this is not my work" portion of that disclaimer is highly relevant and useful information for interpreting the blog. The afformentioned IANAL disclaimer helps readers to understand whether your opinion has any stronger basis in law than their own.
I also strongly suspect that some disclaimers would have legal value in the event of someone misusing information being dispensed, but IANAL.