In the last year, I’ve messaged five agencies in three cities and only one responded. Even one that I had visited before did not respond when I reached out more recently, despite appearing to be in active service. Is this related to security? It’s pretty annoying when I just want to hobby.

Maybe you didnt provide the necessary info and they thought you were a time waster? Maybe they needed to be contacted by email for a first time client? Maybe they are not getting your communications? Could be many reasons.  
.
If you only have a 20% response rate, spread out over multiple agencies, the odds are it is something wrong on your end but without all the info needed to determine cause, there is just no way for us to know.

your review history, 2017 was your last and then the newest is 2025.
You just might be off their active list.
I know you say you 'appear' to be active.
They might not see it that way.

How did you message them? Maybe your intro has red flags?

If you just said "hey." don't expect a response.

Your number could've been flagged.

in your review history, it could appear to a booker that you are retired from the hobby and an imposter has hijacked your username and has already given it a bad reputation.

You just made a baseless assumption that he used his ter username while attempting to get an answer from the agencies.  

for indy agencies (not Kgirl agencies) that I have reviews under so they know I'm a legit customer.   There are others here that do that, too.  Is that a newsflash for you?  

Just because some people might do it, doesn't mean that many or even most do. Most don't.  

Damn. How many alias on this board do you have?

And one user account

Sounds like that guy isnt within the rules

the rules state, but you are allowed to change it every three months.  In my time here, I theoretically could have gone through over 70 aliases, but I have not used that many.  It's not uncommon for me to write a few reviews before I change to a new one.  If you had been here longer, you would probably know this.  I don't know if Rocket knows it or not.  I remember the first day he showed up here, fresh off the Monkey site in mid-2020. Lol

However, over time you can have your alias reset and create a different one. This does require admin help though.

I know this. I don't see what it has to do with anything in this thread though. For anyone doing reviews and if they are honest in their reviews, they do themselves a disservice if they somehow expose their username or alias to an agency or an org.  

Been here around 25 years.  

He didn't say he'd "had over 70 aliases." He said he COULD have.
"I theoretically could have gone through over 70 aliases, but I have not used that many."

I've never been questioned by any provider or agency about whether or not I'm a member here. A few ladies knew only because we interacted here early on and eventually met.

You are allowed to switch back to an alias you have used before, as long as you comply with the "one-at-a-time" rule.  I've done it a few times.  However, if you switch back, you are stuck with it for 90 days, the same as if it was a new one.  This means you CAN post under an old alias if you switch back to that alias as your CURRENT alias.  Reviews remain under the old alias name as well.  I just checked some of my old aliases and they each have their original posts and reviews.  Some of my aliases I have used for more than ONE 90-day period.  

You seem to reach out to a certain type of agency or wanna play in a certain sandbox.
When you first started, those agencies gave you a lot of leadway as to what you can ask. They had patience.
Nowadays, those type of agencies don’t like alot of questions being asked, its name ,rank and serial number. Anything more then that, its “click”
So my suggestion is less talk more action or keep it simple  
Now… carry on