The cable giant stands to gain significantly from the Trump administration's business-friendly policies
You say that, but it's relative. If the economy tanks, then so will Comcast. They may gain on the swings, but that doesn't really help if they lose on the roundabouts.
Also, if I was a business leader with something to gain from Trump, I would still be worried: Even if I gain significantly from his policies, I'd be thinking long term and be really worried because in four years time† there's going to be a massive backlash. Trump's biggest legacy could be to make the Republicans virtually unelectable for the next decade or two.
(† or possibly sooner, at this rate)