Why do fearful avoidants get into a rebound straight away?

Why ? She is already in one literally a month since we last talked, where she said the usual shit like “oh I love you and forever will” “I need time to focus on myself and can’t be in relationships” even said “ I vow to not date anyone” “I hate men anyway other than you so” Even asked to meet up within a few months and wanted to wish me happy bday which is next month ( not getting a message I know ) Has removed me off everything, deleted my contact and yeh

Why do they do this shit man, why do they say things like this, just to then go against them, like everything is a lie, it’s like they know they are fucked up so they try do same to you, they know wtf they are doing

I wish I could love her still which I do, but the more time that goes by, the more things unfold and the truth starts coming, everything starts making sense, and it’s heartbreaking man, this is the person who I done so much for and gave my heart to, this is the person that done the same and claimed to have loved me