First of all, it does take balls. Look at the response he's getting - he is ridiculed, flamed, called a grifter, and bullied. And he put his reputation as a professor and academic on the line. He had risked his career to do this.
AFAIK he did make some arguments about both oumuamua and those other interstellar objects. His claims aren't "evidence free". He has insufficient evidence and I'm not convinced, but without people willing to pursue evidence out of their comfort zone, science can't make discoveries.
Despite 40 years of research, Tarter risked nothing. She never put her reputation on the line. Neither did her colleagues. You can't get funding for something you yourself aren't willing to take risks on. Their cautiousness and lack of confidence and aversion to taking personal career risks reflects on their own confidence in the subject, and any person that would've considered funding them reads those signals and acts accordingly.
He's the first to have taken a personal risk, and taking a personal risk is the only way to convince others to follow you with monetary risk. "performative masculinity", also known as having balls and self-confidence and taking personal risks, is a precondition to getting others to follow you because you can only lead by example. Women can do it just like men - but it is usually a masculine trait.
If you're a feminist and you still don't get how men are more successful in some areas, you could cry about masculinity, but maybe you should learn from them that what it takes is taking personal risks and leading by example, and getting over your personal risk-aversion. And if you can't grow some balls and get over your personal risk aversion, at least have the decency to appreciate those taking personal risks to further a common cause. How the hell is Loeb her enemy in your twisted mind?!
For every man you see at the top, there are 10 men at the bottom whose personal risk failed. Most likely, Loeb will be one of them. I'm actually going to bet on that. While Tarter will continue with her comfortable job with mediocre funding, or maybe bigger funding thanks to Loeb. He'll be the one with a ruined career, not Tarter. So easy to cry "toxic masculinity" when he's in the spotlight, lets see whether Tarter will wish to swap places in 10 years after he's failed. Then tell me with complete honesty which action was the harder one to do.
That's exactly toxic feminism. Pure envy towards the men taking the risks that you couldn't muster the courage to take. Next time, take the risk yourself or be grateful to those that have the courage to take risks that benefit you. Women can be just as brave, look at Greta Thunberg. I don't believe her either by the way (you can look my post history about climate change), but she did have more effect than many "evidence-builders" and she also took a greater risk, and I appreciate that.