Online, the attackers always have the upper hand, you know...
The Internet (the open Web) once hosted various information resources, but they either failed to monetize or simply became dysfunctional due to trolling scripts and gradually disappeared. Generally, systems vulnerable to trolling disappeared first.
Today, only a small portion of the open web remains, alongside the vast deep web and personal communications... The functional web now exists almost exclusively under the umbrella of large corporations, with everything else being minimal. Trends play a role, but I believe the harsh reality outside that sphere is the biggest factor.
The only things I've seen that actually work against online trolls are legal action (or the threat of it) and physical pressure.
Compared to those, Cloudflare Turnstile, reCAPTCHA, SMS authentication, and such are somewhat less but effective—though they cost money. But trolls need money to counter them too.
Otherwise, the victim site just has to divert resources away from existing users, which is usually the troll's tactical goal.
And if the site doesn't explain anything to its users, they'll feel like, “Hey, we're being bullied for no reason.” That's also a troll's tactical goal.
Accountability is important, right... At least we can avoid the mental divisions caused by misunderstandings and miscommunication.