I should clarify: I don't think they're adding backdoors maliciously. It's their conduct -- proceeding despite the concerns raised, attacking critics, etc. -- that is greedy and malicious.
Now, that I am inclined to agree with :) And fact is - using the device as shipped to us is more dangerous than not using it at all. Anybody within WiFi range can basically do whatever they want.
This is an arena in which malice could plausibly try to disguise itself as incompetence. It's fine to give people the benefit of that doubt, but it is a doubt.