I've always thought backing into a restricted parking space utterly illogical at best. You're not looking forward while pulling into highly restricted space, but doing so while going into unrestricted space. You shouldn't need your vehicle pointed out of a space to achieve situational awareness, either.
I have to admit, for LEOs it does make sense (do the basakwards parking at leisure, pull out in haste) but I doubt it does for anyone else. My neighbor does this all the time in her little garage, I always have to wait.
Your experience does not reflect proficiency in the use of your side mirrors. It is easier, by an order of magnitude, to tell how close you are getting to the obstacles on either side when observing the gaps, or lack thereof in the mirrors while reversing, versus using depth-perception to judge it when you are pulling in forward. Add to that the arc that the rear wheels make being inside of the arc that the front wheels make, and it becomes apparent that the tighter the parking space (aisle width being the key here), the more backing in becomes the preferred option.
Let me state it even more clearly, and in absolutes. Ignoring the issue of judging distances and the situational awareness for a moment, there comes a point where the geometry of the space, the aisle, the steering axle, and the non-steering axle, make it impossible to pull in forward while it is still possible to pull in backward.
Now, going back to grey areas of preferences, judgments, and perceptions, the closer that you get to the aforementioned absolute limit of being possible to pull in forward, the more that the overall equation begins to favor backing in. The longer your wheelbase, the sooner that point comes.
If your experience does not include long wheelbase vehicles, your observations are reasonable, and are likely a matter of preference. If you do find yourself driving a long wheel-base vehicle, please try some practice in a safe place with some cones before coming into the tight parking space next to me. I guarantee that you will find backing in preferable to pulling in forward at that moment.
For reference, my three most often driven vehicles are a 2010 Tacoma ex-cab, a 2004 LeSabre, and a 1992 F350 crew-cab long-bed. The only one that I regularly need to back into the spot is the F350, but the other two are often cocked at an angle in the spot, and thereafter strongly favor backing out to the side where I came in, thereby limiting my options for which direction I leave the parking lot.
Sure, I could jocky her back and forth a couple of times to get her straight, but that isn't necessary when I back in. I think that is the issue that started this conversation.