There's no reason for people to stop hearing the Gospel by stopping their ears unless they want to reject what they are hearing.
Otherwise, as Paul puts it, hearing leads to believing. So if hearing leads to believing and in chapter 7 hearing leads to stopping their ears, it means the Gospel was penetrating their souls like it is supposed to do and does in every example we have in the Bible. It's also clear they were hearing and decided they wanted nothing to do with what they were hearing.
We have 5 examples of those who heard did this or that. That's more scripture than you can provide to say otherwise.
The context of 7th chapter of Acts, in general, provides examples of unbeliever's jealousy of believers. Jealousy is different from envy, nuanced from it in that it begrudges what the holder believes is rightfully his, as opposed to envy which desires to have what the other possesses....
I started this reply I don't know how many days ago, so I don't remember the point I was working toward...
but I'm sure it was relevant and might've even been helpful, somehow, so I decided to finish the post rather than just simply deleting it for having so far behind.
In Stephen's case, he looked up and claimed that He saw God... which enraged them, and they drug him out and hurled stones at him. And Stephen fell asleep, and I daresay he fell asleep like he was being tucked into a comfy bed.
So, what were these so jealous, or envious, of even though Stephen just presented them with the message that, if heard, would grant them with exactly what he possessed also? However, that Stephen, just prior to having said that He saw Jesus standing, he had just told them that they had failed to keep the law (and in their mind, this translated to "you failed to keep the law, but I have not...since I can see God and you cannot) provides some insight that they were stirred up with envy.... or perhaps both envy and jealousy, in believing Stephen 'taking' from them the righteousness they'd works so hard to project (although the effort was toward their friends' regard rather than God's).
And so, they just weren't having it because, up to that point, their peers had thought so much of them.
Yes, I'm leaning toward envy stopping up one ear and jealousy stopping up the other.