Two main thoughts: One, you can't change the pH of your skin permanently. Your skin has an acidic pH, and really alkaline things - especially those you don't rinse off for a while - are going to irritate it. (You don't want to change the pH of your skin as bad things can happen, like horrible diseases, cuts, and irritation!)
Second, and a more general comment, if a product doesn't work for you, don't use it. Don't think you're doing something wrong. The product is alkaline, which will irritate many many people, not just those with sensitive skin types.
I see posts on blogs that remind me a bit of faith healers. If the product doesn't work for you, it must be all about what you're doing wrong, and that's not the case. I see this with conditioner washing, baking soda and vinegar washing, and with homemade deodorant. I had a very lengthy interchange with a woman who believed that catnip was a conditioner, and anyone who said it didn't work for them was shouting down by allegations they weren't doing something properly. (Catnip is no more a conditioner than cat hair in our products as it lacks any qualities that would make it a conditioner.) You aren't doing something wrong if a less traditional way of doing things isn't working for you. In fact, if it's working for one person and not for the rest, odds are pretty good they're doing something they either don't realize they're doing or something they aren't sharing or they are freaks who can handle stuff no one else can! (I use "freak" in the nicest sense of the word.)
If you want to use a homemade deodorant filled with an alkaline ingredient like baking soda, then do it, but don't feel bad if it doesn't work for you. Lots of people swear by it, and there might be something there that appeals to you.
One of the pages I read implied that a blogger was trying to convince you that these were bad for you and wanted you to use storebought instead. I don't think it was a reference to me as I think the writer would have her head explode if she visited here and saw the ingredients I used, but if it was I want to make it clear that you are more than welcome to use what you want as a deodorant or anti-perspirant. Not to sound horrible, but I don't really care either way. I'm just trying to offer some information to help you figure out how to make products. I'm not affiliated with any companies, let alone one that makes anti-perspirants. I recommended the Secret cocoa butter one because it smells really great.
Making deodorants (some thoughts and links)
Want to know more? Visit LiseLise's Natural Skin Care blog as she's incredibly knowledgeable about this topic! Check out her informal survey of people who had skin reactions to baking soda deodorants. It's around 85%! Eek! And read this post based on a conversation with someone about baking soda deodorants. Finally, if you want to make a natural deodorant, check out her recipe using clay instead of baking soda! Her blog is such an amazing resource for all kinds of things, but she really knows her baking soda deodorant stuff!