Is there a way to restrict access for active leechers to own public giveaways?

Nope, there is no way around it with public giveaways.

Use sgtools.info.

Not even external tools can do that currently, and likely won't - there has been requests for SGTools to add a "last GA date" filter, but it's unplanned.

By now I'd already be kind of satisfied if cg gave us better (or any) tools to identify blacklist candidates or if handling the blacklist itself and its limit would be less of a pain.

You could join a group (like Unlucky 7 for unlucky people etc), and then make group only giveaways perhaps?

Not even sgtools will help you with that, best you can do is find a suitable group which do not accept such people. Or join some group you want support and filter such people by blacklist, 1000 spots should be enough for such way

For what it's worth, I used to be a decent contributor. It wasn't full price AAA titles or anything, but I managed to get my level up pretty decently. Then a series of unfortunate events happened, and right now I'm struggling just to pay my static monthly bills, let alone buy games for other people. Every time I think I'm about to have some excess money, something comes up. The most recent was a $900 bill for a cracked windshield because apparently commercial trucks hauling rocks are immune to the law that says any load must be secured at all times. Before that it was a $1200 bill because I hit a pothole in the road that the city can't be bothered to fix, and it bent something under the car (I don't know enough about cars to understand what happened, but the wheel was at a funny angle after that). When I'm only MAKING $1200 a month (disability) and still have to pay rent, food, gas, insurance, etc ... it's not so easy these days. So ... I guess I'll just have to stop using the site altogether since apparently I'm now just a leech because I haven't been able to buy video games to give to other people for over a year, even though the one thing I've won in the past 9 months was a DLC that I didn't even receive.

Mmm. Maybe try a group where you have to make monthly giveaways, or have some decent ratio in the group or you will be kicked. There are many, like Pandora, mini jedi training, jedi training, bundle quest, Knights Of Havenshire, new very positive, new very giveaway 2.0, total war arena, etc, etc.

unfortunately you cant make any restrictions other than by level, even sgtools doesnt have a way to restrict users that havent made any giveaway in years. the only solution is the whitelist or creating your own group with rules you are happy with(thats what i did). just remember that creating your own group also needs some time to manage it.

https://www.steamgifts.com/discussion/eg6IX/additional-giveaways-restriction

That was my idea. Poll suggest that most people were against it xD