I don't really understand what lawyers have to do with the discussion but I certainly do believe you that you had an in-house proxy that did MITM HTTPS traffic. Lots of businesses do. The problem is you said "let me tell you it is quite easy to MITM by any company owning part of the connection" using that as your example. While your anecdote may be true, the statement it is trying to support simply isn't true and neither was your description of how SSL works (eg the proxy server being able to disable the client libraries SSL checks).

So it's not that I don't believe your anecdote - I'm sure that did happen in some form or other - but the nature of the exploit either isn't how you described or is so old and long since patched that it hasn't been exploitable in more than a decade thus isn't relevant to the statement you were trying to support.