Those are both examples of incomplete markings that don't include the diode symbols. Sat splitters have to pass power from any of the "output"" ports back to the "input" port so the receiver can power the dish-mounted electronics.
The Ideal splitter you indicated is one of my favorites as is the Holland HFS-2D whose label does properly indicates the internal function.
If polarity matters for DC-passthrough (and it would in the case of the splitter that is performing antenna combiner duty), there is at least one splitter out there that does not used DC-blocking capacitors on the output so it doesn't need diodes. That would be the Channel Plus 2512A.