At my old university (staff, not student), 28 working days was the stipulated turn-around for marking, unless staff applied for a longer deadline e.g. where there were instances of suspected plagiarism which needed investigating before return of any work.
This turn-around is really not that long. Often a cohort of students might be well over 200 students, multiply that by 4, for a 4 year degree and a lecturer can easily be marking 800+ essays at any one time. At the same time, the same lecturer might be supervising dissertation students or postgrad research students, postdocs, writing grant applications (my last institution insisted all staff obtained (not just applied for) at least £100k of research funding per year as PI), writing papers, teaching, interviewing UCAS applicants and, yes, talking at international conferences etc - something which raises the lecturer's international reputation in the field, which increases their chances of obtaining funding, which attracts more students to the university. Teaching is a teeny, tiny part of an academic's role but many undergrads think is their only job and for most of my ex-colleagues, routinely working until gone midnight was not uncommon. Further, academics do not enjoy the same holidays as the students.
Probably the reason why more fuss is not made about the strike is that:
- Lecturers striking does not cause enough disruption to the general population for politicians to make a fuss about/worry about losing votes
- At many institutions, pressure will be put on non-striking staff to undermine the efforts of their striking colleagues and do the marking for them
The majority of lecturers have had effective pay cuts for a number of years now (as have other public sector workers). Pensions have been changed from final salary to average salary and working conditions have been slowly eroded. Why shouldn't academics have a right to make a stand regarding their working conditions.