This passage is about meaningful prayer in order to form a spiritual bond with God. Often times people would use prayer as a means of receiving praise. They would purposely go out in public to draw attention to themselves so others would think highly of them. However, Jesus spoke against this, encouraging everyone to go somewhere private to pray and use prayer as a means of meditation and to strengthen ones relationship with God, not their social status. The original people hearing this understood it rather clearly as Jesus did intend this triad to be interpreted literally giving them thorough instructions on how to pray.
I personally feel that in today's society there is almost a stigma surrounding religion and so public
prayer wouldn't be a means of seeking social status as it used to be. However, there is still that challenge of going to pray without anyone knowing especially since my family regularly comes into my room to check on me. There's also the aspect of Church where everyone can see you and although I don't think Jesus literally meant to go into just your room, it's important to focus on prayer when at Church and not to be boastful while praying. I think the ethic of this passage is about having the proper intention, in specific to prayer but much more than just that. The passage reinforces the idea that a persons motivation to do good deeds must be righteous and from a pure heart.
People are called to respond in a rather literal sense by praying with the purpose of becoming closer to God and not for show. Additionally, people are called to the ethical interpretation of this passage as well and are asked to do things with a good intention as oppose to doing something simply for praise and recognition.