Sure they do.1. They don't list their methodology or make it transparent
The CNN Poll was conducted by SSRS April 25 through April 28 among a random national sample of 1,007 adults reached on landlines or cellphones by a live interviewer. Results for the full sample have a margin of sampling error of plus or minus 3.8 percentage points, for the subsample of 411 Democrats and Democratic-leaning independents who are registered to vote, it is 5.9 points.
2. The data cannot be checked against objective results unlike Exit polling that can be confirmed how accurate it is
This is a non-argument. The vast majority of polling doesn't have anything to do with exit polling, so what you're in effect saying is that the entire science of polling is inherently flawed. At that point you might as well ignore any and all polling, including Trump approval rating polls.
3. There are well established statistical sampling problems with both landline calling and internet polling being inherently not representative
Good thing that they used both landlines and cellphones for their polling, then.