Parasites themselves are neutral sites, that generally receive quality links and extremely quality content that Google naturally wants to rank for.
For example, if you open a pledge in Change.org, to save the Amazonas, and link to your wonderful site "SaveTheAmazonas.Com" with 2 million signatures, appearing the front page of Change.org for half the year, trust me that your site will appear top Google SERPS for anything related to the keyword "save" and "amazonas". This is not an opinion, this is a reality.
Now, if you create a campaign like "we want cheaper v-bucks for fornite" in Change.org and you put a link to your CPA content-locked offer about "free v-buck generator" it's unlikely that you will appear anywhere near the front page of change.org for a milisecond, but you may appear somewhere in the page 20 of the section "economics" within Change.org. This has a very low OPR within Change.org but still worthy.
Now, considering that Change.org has a monstrous authority, blasting this site is irrelevant for them, and irrelevant for Google, but certain links in the blast will be good enough to stick and give a certain amount of tier 2 link juice to that particular page within Change.org. So any link within that page. So, despite having a low OPR, the IPR will be average, low or medium, and this will positively impact your site for almost free, but the time you need to make this happen.