I am willing to accept "a single steroid cycle can cause testosterone levels to be permanently lower" but I cann't accept "and most likely will" because suddenly it becomes a blanket statement. I think Movin_weight's response was pretty spot on.
How old is the user? What PH did they take, what dosage, and how long was the cycle? I don't know what the least "damaging" PH is but a 4 week cycle of that at a low dosage for a 40 year old male cannot be lumped in the same category as a 19 year old that takes the harshest PH for max duration with poor support and PCT. They just can't be lumped together.
What we need is a test of subjects in a certain age group, using a specific dosage of a specific PH and witness that the test levels never return to the expected range of test for their age, activity, diet, sleep etc etc. We'd have to witness that none of them returned to expected levels. Once we have someone that DOES return to expected levels it no longer is an absolute blanket statement. There are factors that prevent a person from returning to normal levels and there are factors that allow someone to return to normal levels.
Don't get me wrong, I'm not saying that a single cycle of a PH, any PH, cannot permanently impact test levels. I don't know enough to say anything on that subject, but once you start throwing blanket statements across such a huge spectrum of scenarios (age, PH, duration, dosage) then you HAVE to throw out the whole argument.
Personally, I agree it sounds like there is a lot more risk of permanent test levels being impacted than the general consensus BUT there are people that also report their test levels return to their baseline after a cycle (some say multiple cycles) so we cannot just say "run a cycle and your test is permanently suppressed".