Unfortunately all disconnections and game crashes counts as leaving the match and will be penalized appropriately. The game server has no way to discern a legitimate disconnection or game crash from one that is forcefully caused by a dishonest player to bypass leaver penalties. You can learn about this policy here:
If you are crashing to the desktop, this is not going to any sort of connection issue and you are not being DoS’ed. Please start with these critical troubleshooting steps.
Please note, the Bug Report forum is not monitored by Blizzard Technical Support, and only by Blizzard’s Quality Assurance Team which tracks for issues such as in-game glitches or bugs as you play Overwatch. Connection issues and crashes are technical support issues. If you need further assistance, please start a new topic in the technical support forum where Blizzard Technical Support and forum MVPs can lend a hand.