I watched the video and there isn't much to criticise about it.
However, we must remember that being a particle physicist is first and foremost a job, like any other. Those in the field have to earn a living and that requires they perform research. If that requires them to postulate new, exotic particles that "need" to be discovered in order to create a GUT, then so be it.
Although as Hossenfelder says, there is no fundamental principle of nature that demands a single, unified theory.
Maybe the real problem is that there are sources of funding available for this work? Ones that seem unaware that every search for particles outside the standard model (for the past 50 years) have failed. But at least with that failure, those involved in the search have managed to make a career out of it.