I can’t speak for Lukas, but I believe he’s referring to the fact there’s a minority in the privacy community who (essentially) say, “THROW BIG TECH OUT NOW. DE-GOOGLE CUZ GOOGLE BIG BAD COMPANY!!1!1!1!11!1!”
This causes confusion for those new to privacy, thinking, “I use Microsoft Word and that means my privacy is completely compromised 
,” or something similar with whatever software they use from those companies.
I myself fell into this, as said earlier, and wasted substantial amounts of time.
But does it maintain or improve the security as well? That’s another question. Overall, it depends on what de-googled OS. Some, such as particular Android OSs, can actually worsen the security of your device.
Always remember: you can’t have privacy without security, but you can have security without privacy. Therefore you need a balance of both. It’s essentially privacy vs security, a struggle between, “Should I erode some privacy for this?” or “Is it worth losing security for this privacy gain?”