I don't work for TurboTax and can't speak for them. TurboTax once told me they did that in Windows XP to protect the user from ID theft since Microsoft was no longer updating Windows XP with security updates. So they made it mandatory. I don't think they should have taken away the "remove pasword" button, however. In my opinion, that should be a personal choice after being informed of the risks. It would have probably been better to have a big popup warning if people wanted to remove it.
I'm sorry, but there does not appear to be a way to remove the password other than with a Windows 7 computer.
ADDENDUM 3/30/17:
Thanks to user blkdimnd below who also reports the password can be removed with a Mac computer as well:
When using a Mac:
"Mac OS X 10.9 or higher and choose Encrypt in the File drop-down list to get to the password controls and remove the password. "
Do you have a trusted relative or friend where you could install TurboTax 2015 long enough to open your file and remove the password? If you do that, be sure their system is secure and that you don't leave traces of your tax info and personal info behind.
