Marler, who is not involved in this weekend's match and has left the England camp for personal reasons, posted his comments on social media earlier this week, briefly deleted his account and then reinstated it, saying he had been trying to "stoke interest".
"The haka for us is a custom. It is part of who we are, our DNA. You can welcome somebody, it is for celebrations, for joy, and also for challenge and we use it as a challenge.
"We believe it is a great tradition of rugby, as it is for all Pacific nations," Robertson added. "It honours where they have come from. It is not just about the All Blacks, it is about us as a country. It means a lot to us."
World Rugby regulations limit how close opposition teams can stand when facing the haka, and England were fined for getting too near before the 2019 World Cup semi-final in Japan, as were France before the 2011 final in New Zealand.
Asked if he felt teams should be able to respond to the challenge on the pitch, Robertson said he believes they should.
"Obviously, it's a respect thing.
"The crowd enjoy it, don't they? It is a special occasion. Some clap, some put a plane over the top. Whatever it is, there is a lot of meaning behind it and it's got to be meaningful and respectful."
Robertson described England's 2019 response as "awesome and respectfully done".
Twickenham crowds traditionally try to drown out the haka's war cries with a rendition of their "Swing Low, Sweet Chariot" anthem.
-Reuters/RNZ