Using the first line of your Summary section is ONE way of making your objective known. It works really well if you want to stay in the same line of work.
If you’re making a career change or you’re an entry-level job seeker with little experience, then you would be better off using a job objective statement. In that case, you might use your first Summary statement to say that you have the skills or knowledge for the job you seek.
The reason some people prefer to use the Summary statement to announce their job objective is because many recruiters say they don’t like job objective statements on resumes. Not all recruiters feel this way, but some do. So the Summary section is a good way around that, as long as you want to stay in the same career field.
Thanks for bringing this up. Hope your job search is doing well!