Unlike the supervision style in my department (CS), I put an enormous effort into supervising my master's students. I meet with each of them twice a week and spend around two hours each week explaining what to do and how to do it.
From the first step, I propose a topic with a potential methodology and ask the student to follow it and give him or her precise instructions on how to proceed. After they successfully complete their theses, I usually push the student to write a paper but never worked out as the students find it meaningless to write papers if they move to industry. Instead, I write papers out of these theses/work and submit them to journals by including the respective student as a co-author. Since I am the one writing the paper, I put myself as the first author and primary contributor. For some journals, it is possible to specify the contribution of every author but for most of them, it is not possible.
I am wondering whether claiming that I am the principal contributor is fair/ethical, given that the student is implementing my ideas and I am who writes the papers. Being the principal contributor is important for some grant applications.
After reading some comments, I think I did not make myself clear. My question is not about whether I should be the first author or not because that what is should be done as the one putting the effort to write the paper. In summary, there is not disagreement between me and the students. They are actually happy that they can have a paper without putting in additional effort. My question is rather about whether should I work on the paper and submit it or not (If not, the paper will never see the light of day). Note that this is done only after the student decline to write the paper and gives his/her consent (e.g. exchanging email after the thesis is completed so that I do not affect his/her decision) that I take the lead.