I never understood this argument. How is it any different for leftist propaganda? This just feels like telling someone to stop thinking because you’re on our team now and we want to make sure you don’t leave.
Your argument seems to suggest :
Listening to far right voices is not too bad if you keep being alert.
The brain of the listener who thinks for themselves will be strong enough to distinguish leftist propaganda and lies from facts and truth.
I fear, looking at the millions of people who are not well informed about some things (say privacy + GAFAM), that this is wishful thinking. Remember the experiment with people in the cinemas where some soft-drink images were almost invisible merged into the movie and made people thirsty and buy more drinks during the break ? In my opinion the human brain is unfortunately not as powerful as people make it believe it is. And I have no big issues in general with leftist propaganda as I’d like to see the planet saved rather than destroyed.