It depends on the ideology you subscribe to. If you look through a intersectional, feminist, marxist lense, it is impossible to be sexist against men, and questioning feminist religion is inherently heteropatriarchal macho capitalist patriarchy talking through you.
If on the other hand you're normal.
Yes, using ones sex as an insult against them is sexist, and and feminism does not have monopoly on "equality", hence disagreeing with them is not equal to opressing them.
To ask that question does not dictate that you are macho, although perhaps it can show a certain ignorance about the enormous variety that exists today in feminism. And it is not bad to ignore it, as long as you are open to know more. I distress myself every day of more and more topics.
The manspreading and the mansplaining are behaviors that occur frequently and that is why they are pointed out. It does not mean that every man has these bad behaviors, that, on the other hand, if he has them, he just needs a bit of good will to correct them.
I think that the media and the networks distort what feminism criticizes and demands, making people believe that we are against heterosexuals, that we are revanchists, that we hate men. None of that is true. And when discussing this in the networks, there is always someone hanging a picture of feminist demonstrations where attitudes that seem violent, without wondering if they really those photos accurately represent the attitude of the photographed or shown if that photo is a representative sample of feminist movements.
Regarding the third wave, I would like to clarify that it is not one, in the sense that there is an immense variety and discussion within feminism that makes it a sum of varied and non-monolithic movements. And I would like to point out, as I mentioned in other responses, the need to create an international feminist front, that all internal debates and concessions between different groups be made there to reach a common international proposal. Because of my frontist conception of politics, I believe that this would favor the accumulation of power, but it would also favor debate and diminish a certain intellectual, inbreeding tendency that small groups usually have.
Today there is no such front and it would not be easy to create it, but with the due capacity of all sectors to give in something, many more things could be achieved than today.
By the way, I encourage you to learn more about the subject. Feminism as a whole, in addition to LGBTI groups, is not only important for the welfare of many people; It is also an exciting terrain. I must confess that I do not know any of this from the theoretical study, which would not hurt me, but from practice. I am not a militant, but I have participated in instances of debate, demonstrations, exchanges, I have followed successful labor claims in jobs performed mostly by women, and I have lived in my own situations of injustice that lead me to have a controversial position even within the feminism.
As I said, with openness and good disposition, although you do not agree with the different feminisms, something you will be able to learn and improve. It's always possible.