Copying a design is not illegal. Unless the design is patented (which it doesn't seem to be or the OP would likely have said so in the article), everyone is free to copy any design they want.
That you wish something was true doesn't make it so, unfortunately.
What is not OK is copying the documentation verbatim, that is copyrighted. However, that is, frankly, the least of the problems (and easiest to rectify) when someone is taking your product idea wholesale.
Those patents are directed towards "method[s] for processing requests for vehicular data", which at first glance appear unrelated to the descriptions of web APIs authenticated by OAuth that Smartcar is complaining about.
That you wish something was true doesn't make it so, unfortunately.
What is not OK is copying the documentation verbatim, that is copyrighted. However, that is, frankly, the least of the problems (and easiest to rectify) when someone is taking your product idea wholesale.