There is no problem with the “gates of ijtihad” being opened (assuming they were ever closed). The problem is when the people opening them are not qualified to do so. A critical part of being qualified for ijtihad is having the ability to identify and excise all the underlying liberal, secular, materialistic assumptions that subtly (or not so subtly) influence how all of us, by virtue of being seeped in modernity, see and understand the world.
A sign of not having this qualification is one’s opinions heavily rely on maqasid and maslaha.
Sometimes it is safer to rely on the opinions hermetically sealed behind sturdy gates.