To each their own. To be fair, I do not see many people 'farming' lower difficulty settings of a raid to get gear for the next level up. Most I know just have a difficulty they aim for, HC in my case, and just progress that. We have a tradition of starting each new raid with a 'blind run', no youtube, guides etc. allowed before opening night, so we can have the fun of discovering our own strat (if you peeked anyway you can not speak or hint), and that is done on N first night . N i run later also, but mostly for social, drunk runs and alt.
I don't think raid difficulties were ever intended to be cleared in sequence (LFR->N->HC->M), but rather offered as alternatives to different player types (Solo, Family and Friends, Social Guilds and Performance oriented guilds). Some people undoubtedly do see it a a ladder, but they are doing it wrong IMHO
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M+ is another story and that is build specifically on incremental difficulty clearing. I realy like it, but again, it is not for all and that is fine.