I'm not sure its a question of respect, its more a question of what you have to offer at this point and the nature of how these things evolve. Collaborations are generally not borne out of "Hey, I like your research and want to help with it" cold emails from folks around the country. They emerge through conversations at conferences, leading to serving as co-investigators on each others grants, etc. I would think it was very weird if someone across the country emailed me to ask to "get involved" with my research somehow without offering some path to doing so. If they want me to serve as a co-investigator on a grant they are submitting...sure. If they want my input on a paper they are writing...we can talk about that. The person asking to get involved is expected to bring something to the table, so I guess the question is...what do you bring to the table at this point that is not available from someone more convenient for them to supervise and with fewer logistical issues to work out (i.e. at their institution)? Given your level and the context, it sounds like you are more asking "Can I be a remote research assistant" rather than a true collaborator. That is fairly rare and a very different thing than a co-investigator on a project.