You are not exploiting the person making the garments, you are exploiting the fact that the cost of living in Bangladesh is far below the cost of living in a Western nation.
The fact that the standard of living in Bangladesh is also lower does not mean that you are exploiting the worker. In fact, in many cases (especially employing them directly online as the GP is suggesting) you are helping to improve their standard of living.
Maybe they are just trying to provoke some thought. They did not make any grand claims regarding levels of exploitation... Not sure why there is always someone trying to get ahead of drama and signal how woke they are despite there being no drama at all.