Avast is not the only antivirus program that does that these days; ESET does it, and Symantec's Norton products do as well IIRC. As everything moves toward TLS, this is pretty much a required step on the client for "Internet Security", and the average person doesn't know or doesn't care.

Largely, you probably should not either if you are trusting the AV client with the rest of your computer. Yes, it can be fucked up and break TLS, but there are a thousand other ways a privileged executable like an AV program could fuck up a lot more of your system. For example, a bunch of CVEs were found in Kaspersky's product by Tavis Ormandy in September, and it appears that a few found in Avast have been made public within the past few days. [1]

[1] https://code.google.com/p/google-security-research/issues/de...