Indeed, but the GP excluded the very next sentence from their sizzle quote:

"Individuals who were both previously infected with SARS-CoV-2 and given a single dose of the vaccine gained additional protection against the Delta variant."

Giving a third dose of the vaccine would probably also give people in the two-dose group additional protection against the Delta variant. The question is whether that additional protection is actually worth the additional doses of vaccine required and the side effects. There are arguments in the mainstream media that giving those extra booster doses would be outright immoral because they could be used on people in the developing world who haven't been vaccinated yet; those arguments never get applied to requiring the previous-infected to get vaccinated, presumably because vaccination is a partisan political topic.

It is easy to stand at a distance and claim that it would be immoral to give booster shots when many countries don't have enough first shots. However, they (WHO) are ignoring the realities of the logistics problems that these countries have in distributing and shipping these vaccines that have stringent storage and utilization requirements. Those countries need to fix their medical distribution systems first to handle the volumes that are really needed for the vaccines that they have access to.

There are multiple vaccines out there that don't have such stringent requirements. Even the J&J vaccine doesn't have those requirements.

As far as I know, only Comirnaty is currently being used as a booster, and it is the most restrictive of all currently approved vaccines.

Honest question, help me understand where this argument is wrong:

if those with natural antibodies are encouraged to get a vaccination in order to gain "additional protection"...

those with a vaccination be encouraged to expose themselves to covid-19 in hope to get a breakthrough infection to generate natural antibodies for "additional protection"?

It's wrong because the risks aren't similar.

Not just to the individual, people getting infected after vaccination are more likely to spread the infection to people that are immunologically naive to the virus than people getting vaccinated after recovery.

Vaccination and natural immunity seems to add to the protection according to the study.