They aren't hated because they are scapegoats, they are hated due to their misogynistic attitudes towards women. Also, they are nowhere near close to the bottom of the hierarchy. Most incels are cis-het men, so despite their issues with living up to gender expectations they are granted a lot of privilege from being a part of those identities.
The term incel has become one frequently used to describe a specific subset of virgin men who happen to be misogynistic towards women, blaming them and society for their issues with getting laid and going into a relationship. They are generally hostile towards sexually active men and women (especially women). That is an essential characteristic of being an incel.
"Nice guys" also aren't usually very nice. They are men who view themselves as being nice and thus believe that entitles them to women's bodies. A lot of these men are quick to turn hostile when denied things, such as sex, hence their poor reputation.
Women aren't valued in society. This comment in of itself proves that, reducing us down to our wombs rather than viewing us as people. Women are treated as objects by wider society.
Well, society doesn't grant privilege based on identity, except in the case of women; women are put up on a pedestal due to the intrinsic value of their womb, and an identity of femininity is built up around it to assist them. Men do not have this intrinsic value, unless they are gifted with congenital traits that women desire. Society bases male value on exemplariness. If one is not exemplary in his appearance, he must make himself exemplary through feats. You yourself admit incels cannot live up to the expectations of their gender. Whether they possess a label of 'cisgender heterosexual male' is utterly irrelevant..
To address your second point, being an incel isn't based on one's convictions, it's a biological reality. The word incel for women seems to serve a dual purpose, one to mock things that they don't like by denying them access to their own sexual marketplace, and two to reinforce social hierarchies by ensuring a certain stratum of men remain anxious to pursue women. Even on this forum I've seen women designate anything that they dislike 'incel', for example, I saw a woman who called Donald Trump an incel.
Regarding your third claim, men are proactive in seeking a partner because biology and society compel them to be. These factors are often drive even platonic intersexual relationships. Men certainly do have an ulterior motive, their biological imperative to reproduce. Thus, we have established that an ulterior motive is irrelevant in this matter, and that therefore it is quite trivial to women whether a man is deferential or not. The labels of 'incel' and 'nice guy' are arbitrarily ascribed to a league of partner-seeking men to devalue and discourage them from seeking a partner, and their application is based on whether the man in question meets the subjective criteria of the female.
I'd also disagree that 'nice guys' usually turn hostile, most soyboys never learn the error of their ways and continue simping while meekly accepting rejection.
With concern to your ultimate paragraph, women possess immense value in a sexual and social sense precisely because of their reproductive capacity, which society has historically and biologically revered. The womb, as crass as it may seem to state, is a locus of value because it determines the future of any lineage. Men, on the other hand, are disposable unless they can distinguish themselves, and this disposability is the very reason men are more likely to be left behind, scorned, or labelled as incels. This is a biological truth, and can be seen anywhere you look. Despite your entitled and romantic view of the world, nothing has value unless it is of practical worth.
Additionally, when have women not treated men like objects?
Throughout history and across cultures, men have often been valued not for their intrinsic humanity but for what they can provide- be it protection, resources, or status. Men are consistently objectified in this transactional sense, expected to demonstrate worth through utility or prowess. This is no less an objectification than what women decry when they are reduced to their physical appearance or reproductive role. Men are judged by superficial criteria such as height, wealth, or status- factors that women openly prioritise in selecting mates. And unlike women, whose inherent reproductive capacity imbues them with value from the outset, men must prove themselves through constant achievement or sacrifice to even be considered worthy of attention.