A homemade pastry has fewer preservatives and additives, you have greater control over the contents, requires a time and effort investment, and is not heavily marketed with prominent placement in grocery stores and appealing, colorful packaging. There are both nutritional and psychological differences between the two that make the homemade version effectively much less unhealthy for you.
False and irrelevant. False, because there's way more than one kind of sugar - glucose, fructose, sucrose, lactose, and more, not to mention cane sugar vs. HFCS. Irrelevant, because there are other non-sugar things in commercial food products that cause you to want to consume the products more, which causes you to consume more sugar. Finally, who says that I put more sugar in my pastries than Hostess does?
I'm not sure if you're missing the point intentionally or unintentionally but while those chemicals sometimes can cause health problems later in life but the sugar is what's causing the calories that are causing the obesity that is causing the health problems we want to mitigate.
The sugar is the problem and both the pastries have the same sugar. The homemade one may be marginally better but it's a distinction without a meaningful difference. The problems caused by oddball chemicals used in industrial food manufacturing are less than a rounding error compared to the problems caused by obesity.
