Not sure what you're trying to say.
1) You were a typical child, having an illegal firearm and making bobs is just school boy fun. : Leading I assume to the idea that we shouldn't get to hung up about it now either.

2) Your confessing to your criminal past, and throwing yourself at the mercy of the courts?

3) If you can get away with a crime then that okay no harm done.

4) We should all be allowed to carry concealed weapons and make bombs to play with.

Only one of the above makes sense to me.

What the author is saying is that in our PC world he'd have been a criminal and his future prospects would have been ruined.

He mentions France, which today has terrorist problems etc., yet a French Citizen can possess, without a licence, guns that would have a NSW citizen locked up quick smart and screaming headlines in the papers.

Well most lads left entirely to their own devices and unsupervised, will get up to similar mischief?

The more intelligent ones will be the most curious? Albeit, a history of animal abuse, killing living things for no other reason than target practice and pleasure, can sometimes lead to worse abuses later on? (Ivan Milat?)?

I had an air rifle, and used to pick the heads of daisies with it, or better yet, tie a bottle to something and set it swinging, then cut the string, with the first shot; and at maximum range.

And later when I took up hunting to remove feral animals eating us out of house and home, a skill that made the task and the invariable head shot, as humane as was possible?

We had a few of those perverts where I went to school and they suffered the potato treatment, which forces a raw spud up the exhaust pipe and plugs it, creating some starting difficulties! Compounded by an inevitable pumping of the loud pedal and an eventual start, albeit one well down on power.

That is until the potato is ejected with a load bang and lots of flame!

Around a dozen potatoes were expended, and several trips to the exhaust repair shop, before these types got the message and moved on; really did go quietly!

I'm sorry, but to this day they and their perverse interest in small boys, still makes my skin crawl and could have suffered far worse at other hands!

So and in summary, many entirely unsupervised small boys/latch kids, would have gotten up to similar mischief!

And it's not all that uncommon to see the moral compass and leadership strengthen as a consequence, and some of the near misses that silly kid's stuff created!

Even so and in the last analysis, kids rarely learn from other's mistakes; unless it's presented almost too graphically!

Like say firing a blank at pointblank range at a piece of particle board; or what a well aimed 50 cal hydraulic round can do to a tree trunk from a mile away!
Rhrosty.

The author here fails to understand that our legal system forgives the many mistakes made by young people and treats then very leniently. None of the things he thinks would happen now would in fact happen.
The law prohibits the publication of the name of a juvenile offender and juvenile offences to not become part of a criminal record.

The argument is fundamentally flawed.

Pipe bombs aren't particularly dangerous to the user, my brother and I made them as well as match head cannons and so forth, the attempt at a flame thrower and a few of our Molotov cocktails resulted in awkward questions when my parents got home: "What happened to your eyebrows?" amd "I just bought your brother those jeans and now look at them!"
Thing is, living way out in the sticks and doing that sort of thing is fine, we also had a disused slate quarry nearby which provided a safe enclosure for such larks, playing with bombs in town probably would have seen us arrested, I knew one kid who got into trouble for setting of a pipe bomb in the street.
We also had the kind of father who even if he caught us doing building devices like that would grab it off us and declare "You silly little buggers, you'll blow your bloody heads off if you do it that way...here I'll show you how to do it properly!"

The author has no right to call himself a "terrorist" or even mention that word because all he was at the time, even by today's standards, was a juvenile delinquent with no ideology whatsoever except for thrill-seeking.