No, not at all. It’s not dangerous. Men put things up their wee-wees with some frequency judging by the sites I’ve seen on the ‘net. My warning was based, at that time, on the assumption that you didn’t know exactly what was wrong, if it was a stricture, where it was located in the seven or eight inches of urethra, how much of the urethra was involved and if there may be multiple areas of constriction. This can be diagnosed by a voiding cystogram which isn’t something you can do at home.
If you know you have a single stricture, say at the area where the urethra enters the corpus spongiosum, know it’s only a few millimeters in length, have a set of sterile sounds and K-Y jelly, gloves and the time and patience to do it yourself, then I imagine it could be done. Please note that I am not advocating you do this.
Since you’ve already seen a physician, albeit a long time ago, and know the nature of your problem, then what you do with it is up to you. How much of a problem is it? Does it take a long time to empty your bladder? Do you have residual urine after you pee? Do you have pain on urination or ejaculation? If you do, then you should see a urologist.