I have a paragraph as follows:
All of us are very receptive to adopting beliefs when we are young, but the idea that “males have to earn females” is not something that is only hammered into kids as they grow up; this is an ongoing process, and most are unaware of it. Our culture is full of expressions that are based on these beliefs and used without any thought of their implications, such as, “that girl is out of your league,” “win her heart,” and “you do not deserve her”. To refer to a woman as being “out of your league” implies that she is unreachable and not even worth pursuing because she is too good for you. In line with this theme of competition comes the expression “win her heart.” This implies that a male must compete for females in some way.
What does the highlighted sentence mean in this paragraph? I rarely find that "In line with" is put at the first of the sentence. Does the writer use inversion in this highlighted sentence? What is "this theme of competition" here? And if I have to rewrite it, how can I do? (sorry because I ask too much and this topic can make some people uncomfortable)