Exactly!!!
Gravity is the great equalizer, it sucks for everyone!!! 
So, you say youâre new to 3D printing. Well, congratulations! Youâve just learned the very first lesson about online models. As my manufacturing engineers often say to my mechanical engineers when handed a CAD drawing: âJust because you can draw a pretty picture on the screen doesnât mean it can be built.â
Rule #1 of online models. Donât assume!!!
Unless the author has provided what I call âproof of lifeââactual photographic evidence of a printed modelâassume they are tricking the community into participating in their experiment to see who will take the bait and waste time and filament, as was likely the case in this example. This model cannot be replicated from the screen to the print bed for all the reasons stated above.
In all seriousness, unless youâre designing the model yourself with the objective of testing the limits of 3D printing design, relying on a third party will likely waste a lot of time and filament on something unprintable if the uploader did not print it themselves. Believe me, I learned that lesson the hard way, but you donât have to since you came to this forum early on. 
If we can save you the frustration of trying to print the unprintable, then we all will have done our good deed for today. 
Refer to this link that was posted a few weeks ago where another forum member learned the same lesson. His experience was similar to your test-case. They had access to the CAD model and ended up modifying their design to be more 3D printer friendly.