My understanding is that they want the hard copy to be like collector's item. This is why they don't mind too much that images have been posted or shared on Instagram or other sites. Instead, this is to create buzz. If someone really wants to own high quality prints of the images, they would purchase the print copy. It is like one can find mp3 of songs all over the internet easily but if you want quality sound, one will still purchase vinyl record.
Whether they have any other intention, I can't comment. But I am still grateful that they operate this way instead of the usual subscription model, i.e. you have to pay and subscribe to the magazine site to view any images. Usually not many images are released in that way and in some cases, just like some OnlyFan creators, they will threaten to take legal action if their images are being posted and shared.
Are the photographers and owner just some pervy people? I don't know them so I can't say. But if this is what it is really about, I would imagine there is no need to create a magazine just to 'trick' models to drop trousers for them. There are other ways in the industry, e.g. casting process. Also, why they would bother to even release any of the images to the publics? So I would rather be thankful that some publishers, photographers and models are willing to work on this magazine so that we are able to celebrate male naked bodies. If you think about it, if they stop the whole thing of Yummyzine tomorrow, those photographers and publishers are likely still get to see the models naked, just not us. It is a bit strange that we should be negative towards it.