ZD: “There are more than one opinions on this topic and you need to decide when to use the more machmir opinion and when to use the Kula.”
What you are saying may be true in certain cases when you are dealing with a topic in which there are different equally-valid opinions. Even then, you probably should ask a sheilah, but if they really are both equally-valid mainstream opinions given by Rabbanim whom you follow in general (and you’re not just choosing to follow their kulas), then it is possible that in some cases you might be right (but even then, you should probably ask a Rav).
I think that what you don’t realize is that that is not the case here. This is not a situation in which there are two equally-valid opinions given. All or most mainstream Rabbanim say that it is assur to shake hands. That is NOT a chumra. It is true that there may be heterim in certain circumstances. And if someone feels that the situation he is in calls for a heter, then he should certainly ask a Rav about it. But that was not the case here. LB did not say that she felt that she couldn’t follow the halacha and wanted a heter. So we should not be discouraging her from following the halacha by telling her that she might lose out by keeping the halacha.
In short, there is a difference between a heter and two equally-valid opinons. As far as I know, this falls in the first category.
Also, your original objection was not based on halacha. It was based on the concern that she would lose out by following halacha, which is why I responded that one never loses out by following halacha.