Madam, you are looking very posh in your fancy dress, if I may say so.

Those earrings are a delight, darling and I love what you did with your hair.

...I'm writing this under the assumption that you don't know any better, because hoo boy is this a bad take

James Cameron legitimately numbers among the small handful of people most qualified to talk about the Titan disaster. The reason why is because being a filmmaker is almost a side project compared to his very real contributions to submersible design, oceanography, and undersea exploration. Cameron has spent decades in the field of undersea science and submarine engineering. He co-designed a submersible called Deepsea Challenger which he personally took to the Challenger Deep, the lowest point of the Marianas Trench and the lowest point on Earth, alone; the first and to date only person to have ever done so solo. His hyperfixation is not the Titanic, it's submersible engineering and undersea exploration in general.
Here's him being presented the Nierenberg Prize (for contributions to oceanography) in 2013:

Note that in the above interview he literally says that he made Titanic essentially just to get the funding to go to the wreck site (and to have the funding to continue to do so decades onward). He's made 33 dives to the wreck of the Titanic.

The reason why he appears in the news is not because he wants to talk about the disaster. It's got little to nothing to do with him having made Titanic (though that is tangentially related). It's because everyone knows that he is an actual, legitimate expert on the issue of submersible engineering (as well as both diving and diving to the Titanic wreck in particular), and so they bombarded him with interview requests and requests for comment. He specifically did not respond to any such requests until after the deaths of the passengers had been confirmed, because he knew that the sub had imploded and they were all dead, and he didn't want to be insensitive and drown everyone's hopes by telling everyone that the search and rescue was pointless. Here's him on ABC News next to his friend and associate Dr. Bob Ballad, the man who discovered the wreck of the Titanic, who is probably the only other person more qualified than Cameron to talk about the recent disaster:

TL;DR: James Cameron is not being interviewed because "he made Titanic"; he's being interviewed because he's a well-known and verifiable submersible engineering and undersea expert.