Despite Opera's excuses, it's clear that this decision has been taken for commercial reasons. The reason itself simply doesn't pass the sniff test of plausibility.
I don't want anything to do with Google. I object to the company, its practices and the insidious power that it is amassing. I used to remove it from my search options. I'm no longer able to do that. I have used duckduckgo, ixquick and qwant interchangeably for some time now.
I object to being corralled into using search engines that Opera has commercial agreements with and for this reason after many years of use, I will be migrating to Firefox where I can at least alter the default search engine.