Remind me how this means Tarantula is Grayson's "self-insertion" character?
She tells the hero that one of the major cornerstones of his entire moral code (in this case, his "no kill" code) is wrong, and he accepts it, and yet, at the end, he's still "not strong enough" to do "what needs to be done," so she does it for him, and he's so devastated by it that he curls up into a cocoon, at which point she infantilizes him and becomes the effective protagonist of the book in his place, since it's her decisions and will that drive the plots forward from then on. Also, she treats her rivals for his love like shit - in the case of Barbara, THROWING A KNIFE AT HER HEAD - and in spite of the fact that Dick has a LIFETIME longer relationship with Barbara than with Tarantula, he LETS TARANTULA GET AWAY WITH THAT SHIT. ALSO, there's the matter of Devin Grayson's utterly creepy and triggery portrayal of Dick's rape itself, which further infantilizes Dick and glamorizes Tarantula, and which Grayson talks about in interviews in equally creepy terms, by insisting that there's a difference between "rape" and "non-consensual sex," and NO THERE FUCKING ISN'T YOU STUPID BIT';AGDSJKGFA'DLGHD
... Also, this marks at least the third time in which Grayson has written a story about Dick having sex with the female character that he's partnered up with - the first being the online Dick/Donna Troy fanfic that she submitted to Denny O'Neil to get hired by DC, and the second being the Nightwing/Huntress mini, both of which cast their preexisting female characters in horribly OOC lights to satisfy her stories - and when you couple this with things she's said in several interviews about how she'd "fallen in love with" Dick ... yeah, it's not exactly that hard to connect the dots.