Why do some websites have weird scrolling mechanics?

Your first example scrolls fine for me, however in both Safari and Chrome https://dlinkers.com/ scrolls abnormally (too) fast.

This has nothing to do with you, your browser, or with Macs in general. The blame is the website/web developer. There is JS somewhere telling it to scroll weird. I am too lazy to find it but its definitely there. If you want to test, disable JS on your browser and while to content won't load (again, more crappy design by the web devs) it will scroll properly.

TBH there's no solution to the problem other than contacting the company. When I come about sites with crappy design, unless I really need it, I will click off and find an alternative site. You don't deserve my business if you can't get basic things correct on your site.

One other solution is manually scrolling with the scroll bar on the right. Permanent viewing of the scroll bars can be enabled in System Preferences > General.