This was not the attitude of top guys in mathematics when I was at university.
Instead, one guy, who won a bunch of major scientific prizes in mathematics was of the view that people when they get scooped by people publishing in 'obscure' languages or non-English journals, were still scooped and that they can just shut up about proving things. Another guy of similar caliber was happy to read and figure out the ideas of papers in Russian and French maths journals, when it was relevant to his work, even though he couldn't read Russian.
Meanwhile, I've heard people speak of Schmidhuber's stuff as obscure because some stuff was in German, which is of course much easier than Russian for English speakers.
Instead, one guy, who won a bunch of major scientific prizes in mathematics was of the view that people when they get scooped by people publishing in 'obscure' languages or non-English journals, were still scooped and that they can just shut up about proving things. Another guy of similar caliber was happy to read and figure out the ideas of papers in Russian and French maths journals, when it was relevant to his work, even though he couldn't read Russian.
Meanwhile, I've heard people speak of Schmidhuber's stuff as obscure because some stuff was in German, which is of course much easier than Russian for English speakers.