I think people are just trying to help with suggestions. But yes, like others, I am struggling to see why you can't embrace these 2 days with your little one.
Most toddler groups and activities are on in the morning because that's the time of day that most mothers struggle. The kids need out and to burn energy off before they nap. Then the afternoons pass more easily.
If you need more of a stay and play type group then have a look around all your local churches. I know one mum who lives quite rurally who set up her own in the local church hall. They took donations of toys to start them off and it's grown and grown to become a huge success.
If you are finding the afternoons to be your more difficult time of day then you need to find ways to pass the time more painlessly. Coffee afternoons at other mums' houses are a great way to share the burden. A PP mentioned some afternoons sitting together with snacks and a movie. You don't have to be running yourself ragged every afternoon.
My toddler wakes from his nap at 2. So that's 5 hours to fill til bedtime. Similar to yourself it's really only 2-5 that's an issue because at 5 we all have dinner together then it's bath time, stories and down for bed at 7. 3 hours from 2-5 can be filled by a movie together, some pottering at home, playing in the garden, helping with laundry, helping to bake, a wander to the shops.
Today we'll be meeting a friend and her toddler at a nearby café where they have a little play area. We'll have a coffee while the kids play. Then I'll take a slow stroll home with him to get some veg for tonight's dinner. I slow the pace to fill the afternoons. Toddlers like to dawdle so it's a good opportunity to slow your own pace of life. Going to by broccoli is literally an activity. Stick some earphones in and listen to an audiobook while you're out with him- I do that. I can still hear him and chatter back to him but I'm also listening to my favourite podcasts 