I found it moderately amusing and not particularly offensive for the idea of inciting violence. Less distasteful than Kathy Griffith's beheading, but still far in the realm of distasteful rather than dangerous.
I think it's out of bounds for the decorum of a President. If there were some jestful tussle between white house reporting and CNN, fine, but Trump has gone full-on offensive toward our press. The most important problem with this here is the President targeting and degrading a specific news outlet globally.
I agree the real problem is the purposefully eroding of the public trust in the news media. We absolutely have to fact check our news outlets and they need to hold up their end by maintaining journalistic integrity, but we've reached the point where everyone claims fake news whenever they hear something they don't like. That's the publics fault too, but our politicians (particularly on the right but both sides are guilty) absolutely
love this and try to fan the flames of distrust as much as they can because anytime bad news is reported they can hide behind it and their base simply won't believe the reports. It erodes journalism and thus they are stripped of their ability to shine the spotlight on the government to hold it accountable.
That's the problem I have with the tweet, moreso even than the immaturity and non-presidential nature of it. Instead we crank the outrage level up to 11 and claim he's inciting violence against the media (just think of the choke slam!). Reasonable people hear that and roll their eyes and rightfully so, the real issue isn't discussed and the status quo continues on like usual.
Trump (and all politicians as well) does a tremendous amount wrong and there needs to be discussion and accountability for it, but that's impossible to do if everyone is simply throwing shit at the other side.