The Stock-Android Contacts-app has a pretty big design-flaw like that. When you open up a contact, it shows you a list of the ways that you can talk to this person. So, either call them, write an SMS, write an e-mail etc.

And the Call-button is for whatever reason merged with the SMS-button. It's just one big button of which 4/5 is for calling and 1/5 to the right opens up the SMS-app. There is an icon representing SMS in that 1/5 of the button, but nothing indicates that it's a separate button from the 4/5 on the left.