Looks like the company in question is Rehook.ai https://www.ycombinator.com/companies/rehook-ai
The APIs look fairly different to me from a brief look through the docs. Apart from both using some resource names like 'Campaigns' and 'Customers' that you'd expect any platform in this space to use, most of the actual endpoints seem to be quite different.
Same with the overall set of features. There are some features in common, but also features on both sides that aren't shared. Website design and copy is totally different.
It seems like OP is unhappy that a competitor is funded by YC and did competitive research in their public community Slack channel. I get that, but I see no evidence that anything was directly copied. It doesn't seem fair to tarnish the reputation of Rehook's founders without evidence to back it up. It's not wrong or illegal to build a competitor to an existing product.
Depending on what they copied it can be anywhere from 'meh' to 'guilty'. What it looks like isn't relevant other than in the context of whether or not it is their original work or not.
Last time I looked, YC doesn't invest much in the companies it accepts.
But I want to focus on the overall tone that you've taken in this discussion: You're playing the victim. It's hurting your credibility.
I assume that you applied to other incubators? That you've tried to pitch other venture capitalists and other sources of funding?
Why aren't you getting what you're looking for? Don't assume it's because everyone is sexist! Be honest with yourself!