I never imagined I would ever say these words;
"to be fair to Google"
And I'm not going to say them now. Say instead;
"to be fair to all search engines".
They default to safe for a good reason, most users do part of their searching at some time in a work or institutional environment where any trace of not-safe-for-work material will get you into big trouble. Defaulting to safe is useful to help people making silly mistakes that could take a lot of explaining away. This has nothing to do with the search engines trying to impose puritan morality on anyone, I'd rather have to spend one second turning it off than spend half an hour in the managers office.
About Google I know nothing, having not used anything except Duck Duck Go for the last seven years. Since DDG keeps no record of who you are, you need to swich off safe every morning and it stays off for the rest of the day, until you restart the browser. One second a day to press a button is a small price to pay in exchange for freedom from being spied upon.