Yes, I feel it was all in good fun. Bowie makes an album called Lowe. Then Lowe makes an album called Bowi. It is done, I feel, as a nod or a tip of the hat to the great, late David Bowie. I feel it's done out of respect and admiration, not competition.
He was respectful of Bowie and was paying tribute to him. This is the kind of thing that artists and artistry thrive on. People collaborate with each other and are inspired by each other. This is how art grows and changes so that they can be better artists and make better art.
Almost as long as there's been a music industry, there's been feud between the performers. Naturally those feuds take form mostly in the form of diss-tracks or diss-albums. So a performer making on in response to having one made about them is just part of the culture of the industry. It might not be all in good fun, but it's certainly just one of those things that they all do.
Though it may seem like it was all in good fun, this was merely a stunt in order to gain popularity for his album. In the entertainment industry, marketing is a must, and what better way to get your brand out than to relate to a pop culture icon. This is the case with relating his album to David Bowie.