Architecture can be defined as the design of built form, often of buildings in which we can live - thereby fulfilling the fundamental human need for shelter. Landscape architecture is concerned with shaping the natural environment in a way that is both aesthetically pleasing and responsive to our needs. In this context, then, the phenomenon of so-called "defensive architecture" - which refers to architectural features that are deliberately hostile to people, such as "anti-homeless spikes" - doesn't really seem like architecture at all.
This Guardian article is a brilliant and impassioned critique of defensive architecture, written by someone who has first-hand experience of being homeless and on the sharp end of the spikes, metaphorically speaking. The author, Alex Andreou, is right to lament the way that public space is becoming increasingly controlled, circumscribed and (effectively) privatised, and to flag up the sheer inhumanity of features that are "considered, designed, approved,
funded and made real with the explicit motive to exclude and harass". They are in that sense offensive rather than defensive, a means of further dehumanising the homeless, who are already treated as a different (sub-)species.
Especially given that homelessness is on the rise, it would show basic decency and compassion if we were to actually acknowledge the scale and typical root causes of the problem, rather than attempting to sweep it under the carpet and pretend it doesn't exist by making our cities as hostile as possible to those who have nowhere else to go.