r/bitcoin also has a vendetta against Coinbase because they're for a blocksize increase. That forum is actually incredibly childish (just read the comments). You don't find the same concentration of complaints in other cryptocurrency reddits, and r/bitcoin definitely is not the only one or the most important.
Coinbase CEO here. This is (sadly) quite accurate.
The other reason you see so many complaints there is that there are many scammers trying to buy digital currency with stolen credentials, and a common scammer tactic is to appear angry (via support channels, or any public forum) in the hopes that we will approve their purchase.
