His criticism is that almost none of the 63 national pavilions showed new architecture, and instead focused on "one-liner installations".
"Pavilion after pavilion was devoid of architecture," he said.
"Pavilions were either given over to one-liner installations, which could be absorbed by stepping in and out for 30 seconds, or to themes that have little to do with architectural design, and were discussed without presenting works of architecture."
National pavilions "refused" to show architecture
The 16th edition of the Venice Architecture Biennale is curated by Yvonne Farrell and Shelley Mc Namara of Grafton Architects. Titled Freespace, the main exhibition aims to highlight the gifts that architects give for free, through good design.
They did this by exhibiting a range of wide range of models, drawings, photographs and films.
Schumacher's criticism is that this approach did not extend to the national pavilions, which are given an open brief to interpret the theme as they choose.
"While Yvonne Farrell and Shelley Mc Namara of Grafton Architects did their job in inviting architects to show their current work, most national pavilions – once more – refused to do so," said Schumacher.
"Instead of being informed about and confronted with the best and most innovative architectural projects or designs of the last two years from the various countries represented, we had to suffer, once more, the usurpation of 'our' pavilions by curators to disseminate their messages, and present themselves via installations," he continued.
The architect particularly criticised the British Pavilion exhibition, which was designed to make a statement about Brexit.
Curated by architecture firm Caruso St John and artist Marcus Taylor, the project saw the existing pavilion left empty and a temporary platform built on the roof.
"The literally empty British Pavilion best illustrates the malaise of these wasted biennales," said Schumacher.
Schumacher "won’t shut up"
Schumacher made a similar point in response to the 2014 edition of the architecture festival, saying that architects need to "stop confusing architecture and art".
In this latest post, Schumacher says he "won’t shut up until matters improve".
He argues that, by not presenting architecture, the curators of the national pavilions are missing one of the biggest opportunities for the profession to present itself to the public.
"This pattern turns the architecture biennale into another art biennale, and our discipline thereby loses its most important global exhibition and communication forum," said Schumacher.
Schumacher, who leads Zaha Hadid Architects, is one of the most outspoken figures in architecture. Earlier this year the architect claimed that unfettered capitalism "can solve the housing crisis", while in 2016 he called social housing and public space to be scrapped.